Peterson and his wife, Gina Cirone, became parents of twins, a boy and a girl, on July 5, 2011. The twins were delivered via surrogate. William has a grown daughter, Maite, who has given him two grandsons.
Peterson's first lead role on stage was with Chicago's Victory Gardens Theater. He played John Dillinger in Dillinger.
William appears on-screen giving updates and instructions during a live, interactive CSI-type stage show geared for children. The show, called CSI: Live!, made its debut in 2008.
William was honored with a star on the Hollywood Walk of Fame in February, 2009.
William Petersen left the regular cast of CSI in 2008. Soon after, he appeared on the Chicago stage performing Conor McPherson's Dublin Carol at the Steppenwolf theater.
He is right-handed.
William Petersen hosts a video shown at the Chicago Field Museum's DNA Discovery Center. The video, which explains the basics of genetics and DNA, is shown to vistors to the exhibit, which opened in April 2008.
In 2007 William Petersen was reunited with director William Friedkin, when Friedkin directed an episode of CSI. Friedkin helped launch Petersen's career by giving him the lead in To Live and Die in L.A. in 1985.
According to a 2007 TVGuide.com article, William Petersen's salary is $500,000 for each episode of CSI: Crime Scene Investigation.
William chose his CSI character's last name, Grissom, as a tribute to Virgil "Gus" Grissom, one of the three American astronauts who were killed in the Apollo 1 launchpad fire in 1967.
Billy was runner up for "Sexiest Boss" in TV Guide's The Sexy Issue (2007).
Billy refused to appear in any other versions of CSI.
After college, Billy and his then wife, Joanne, spent time in Spain, where they started a Shakespeare company in the Basque region.
Billy met his first wife, Joanne, when the two attended the same high school in Boise, Idaho. They have one child, a daughter named Maite, born in 1975. Billy became a grandfather in October 2003. He has a grandchild named Mazrik William.
Billy's grades were so poor in college that he wasn't allowed to play football. He began taking theater classes to raise his Grade Point Average.
Petersen played football, baseball and basketball while in high school.
When he was 15 Billy ran away to Boise, Idaho, to live with an older brother.
William Petersen's parents owned a furniture store in Evanston, Illinois.
William Petersen has five siblings; Billy is the youngest.
Petersen played members of the famous Kennedy family twice. He played Joseph P. Kennedy in The Kennedy's of Massachusetts (1990), a TV miniseries, and he played John F. Kennedy in The Rat Pack (1998) on HBO.
Petersen attended Idaho State University on a football scholarship. William says he made the football team at Idaho State as a punt returner because of his ability to run backwards really fast.
An avid Chicago Cubs fan, he sings the seventh inning stretch at Wrigley Field every year and also narrated the documentary "Beyond The Ivy" about Wrigley Field.
William's role as Gil Grissom shares the number 82 spot with Catherine Willows in "Bravo's 100 Greatest TV Characters".
He is of Danish descent.
He turned down a major part in Michael Mann's Heat (1995).
He turned down a major part in Martin Scorsese's Goodfellas (1990).
He attended Bishop Kelly High School in Boise, Idaho, where he had the nickname, "Wild Man." He wears his old football jersey from that school in most of his movies.
He appeared uncredited in the noir thriller Mulholland Falls.
Petersen's favorite pigout food is the Double cheeseburgers at the Gaslight on Halsted Street in Chicago.
When William was younger he was into rock concerts, drinking and the usual pot smoking. He called it "General brattiness."
William is alleged to have passed on a part in Oliver Stone's Platoon, as it would have kept him away from his family.
2001 - Nomination for a TV Guide Award for Actor of the Year in a New Series for: CSI: Crime Scene Investigation.
2002 – Nomination for a Golden Satellite Award for Best Performance by an Actor in a Series, Drama for: CSI: Crime Scene Investigation.
2002 - William & co. were nominated for an Emmy for Outstanding Drama Series for: CSI: Crime Scene Investigation.
2003 - William & co. were nominated for the Television Producer of the Year Award in Episodic Drama for: CSI: Crime Scene Investigation.
2004 - William & co. were nominated for Television Producer of the Year Award in Episodic Drama for: CSI: Crime Scene Investigation.
2004 – Nomination for a Golden Globe for Best Performance by an Actor in a Television Series - Drama for: CSI: Crime Scene Investigation.
2005 - William & co. won the Screen Actors Guild Award for Outstanding Performance by an Ensemble in a Drama Series for: CSI: Crime Scene Investigation.
William owns the rights of James Ellroy's crime novel Clandestine.
William shares his birthday with actor Alan Rickman.
William recently testified before the Senate Judiciary Committee on increased funding for crime labs.
William's nickname is Billy.
William married girlfriend Gina Cirone in 2003.
Billy owns a production company called High Horse.
Billy attended the renowned Steppenwolf Company in the early years of his career. In 2008, after stepping down from his lead role in CSI to do more theater, Billy joined the Steppenwolf Theater ensemble.
William is approximately 5'11" tall.
William Petersen: (on receiving a star on the Hollywood Walk of Fame) I have never considered anything like this happening in my life. It has always been one job after another, trying to do good work. Who wouldn't be happy with that?... To be on the same street as Jack Benny, Bob Hope and Jerry Lewis, what better thing is there?
William Petersen: (on leaving CSI in 2008) I won't miss Grissom. It was a complete life for me that's reached its end, and it's reached it in the right way, I think. So I won't miss Grissom. And I hope that the audience won't miss him either.
William Petersen: (on joining the Steppenwolf Theater Company in 2008) I just want to be on the stage telling stories.
William Petersen: (on leaving the cast of CSI in the ninth season) The decision was coming over a while. I mean, I wasn't sure I was going to do Season 5. I did the show longer because of everyone I work with, and I'm really proud of what everyone's done. I'm also concerned with the audience.
William Petersen: (on leaving the cast of CSI in the ninth season) I'm going to come back and see the guys on set doing episodes I'm not in. And I'm staying on as a producer. The show is important to me, and I'm not abandoning it. I'm coming back on some level. I just don't know what yet.
William Petersen: (When asked if he thinks of quitting) And you have fans. You can't discout them. These people have made you. You have to be responsible to them, more than anything else, really.
William Petersen: We were talking about how we're having friends now who are passing away. So you say, "What should I do with the rest of my life? Do I want to be the guy who was on CSI? What guy do I want to be?"
William Petersen: (On Grissom's revelation of his romance with Sara) I'm not even sure that Grissom realized that he was saying it or that at the moment, he didn't realize that everybody was hearing it. It was a revelation on his part. And again more importantly that's really what has come to pass on this season is the realization on Grissom's part that...he loves someone.
William Petersen: (On the CSI season 7 finale) The best way to put this is that, you know, i'm not a huge fan of cliffhangers endings. However I think because of what we've done with the whole minituare killer story line that in a way we've earned this ending, you know? It's not something that you can just wrap up quickly and walk away from it.
William Petersen: (on stage fright) I had panic attacks during rehearsal. There were times when I really thought I wasn't going to be able to do it.
William Petersen: (what he brought back from his theatre experience) I brought back some ideas for my character and Jorja's character and that relationship that wouldn't have come into play in the same way had we not had that scene [when I left].
William Petersen: (on being typecast) I think you can find yourself on one of these shows for a long period of time and think that all you'll ever be able to do is that character. Certainly people think of you that way.
William Petersen: (on taking a break from CSI to do a stage play) I had the feeling that if I didn't get back on stage, I wouldn't want to go back. It's happened to a lot of actors where the further away from the theater you get, the more terrified of it you become.
William Petersen: (on Dog Eat Dog) That aired the night of Thanksgiving in America, and uh people just stuff themselves on Thanksgiving so we thought it would be appropriate to have some guy die of overeating.
William Petersen: (On Lady Heather) She's sort of the-the quintessential anthropological study for Grissom. You know she's-she's just so fascinating to him because she's so...out there.
William Petersen: Grissom is a character who doesn't really want people poking around in his life. He likes to poke around in his work.
Curt Columbus: (Artistic Director of Theatre on the Lake recalling a time when he saw William Petersen, who already had gotten his big break in movies, hanging lights at the old Organic space in the 1980s.) I thought, if Bill Petersen can hang lights, who am I to think I'm above doing that? I tell my students, don't say no to anything that's reasonable. Even terrible projects are a learning experience.
William Petersen: There has never been a show that has followed the criminalist, they follow the cops, and the cops are always chasing after lies. They chase down whoever is lying to them and try to get them to not lie. And these guys (the criminalists) use irrefutable evidence to pinpoint the truth. That's what drew me to it. I've been telling anybody who would listen that I wanted to do a series for the last 10 years. But I wouldn't do it if I was just another cop pushing bad guys up against the wall.
William Petersen: (On the criminalists on the show) They're scientists and nerds, but with DNA and other scientific investigation techniques, they're like Sherlock Holmes for the new millennium.
William Petersen: Their argument was, everybody else is going to start copying the show, so why not us? My attitude was, well then everybody else do it. Don't rip yourself off.
William Petersen: (on marrying young) I was only 21, and there were many things I didn't know. I was trying to be a man and I wasn't ready for it.
William Petersen: (concerning his role in Manhunter) After Manhunter, I had to actually kill off the character. I cut off most of my hair and dyed it blonde. I changed my whole look just to get rid of him.
William Petersen: Chicago is such a blue-collar, middle-American city, it's just real people, you know? Nobody has an agenda that fits into yours. I get recognized and stuff but they don't give a sh*t about that. They just want to know whether or not you're going to buy them a beer.
William Petersen: I was horrible at science and math. I couldn't pass a test to save my life! I'm surprised that it didn't take me until I was 20 to graduate. That's why my role is so cool - Grissom is the complete opposite of me.
William Petersen: (on CSI spinoffs) Two years from now, there'll be another one in Philadelphia and one in Toledo. If it works, they're going to use it until it doesn't work anymore. You can't tell them the golden egg is going to get broken.
William Petersen: (on reality shows) The reality thing is getting tired now, because it's rubber-stamped out. They're all the same show, just set in a different place.
William Petersen: (on CSI fans) We thought we would have a niche audience of loyal viewers like X-Files or West Wing. But we have a huge audience that crosses all kinds of boundaries. It's unique. It's bizarre.
William Petersen: When we get involved in the ratings, then we're doing the network's job. We need to focus on our work.
William Petersen: (on acting on television) I was a little bit of a snob in that way. I was afraid I'd lose my soul and my freedom. What I've discovered is that great drama can exist in any medium.
William Petersen: (on playing Gil Grissom) I didn't want to play a lawyer, I didn't want to play a doctor, I didn't want to play a divorced guy, I didn't want to play a married guy. Dozens of shows have come my way, but I couldn't see doing them because there wasn't anything new in them for me. Then there was this and I went, 'Yes, yes, yes, this is the guy!'
William Petersen: (on CSI's success) We knew all along we were making a good show, so its success was not a surprise to me. What has surprised me is the magnitude of this show's success. More people see me now in one episode than saw me in 20 years of movies and theater!
William Petersen: Grissom is pretty asexual. He's not that interested in anything other than work - except for Lady Heather. She's the closest to getting his heart of anyone.
William Petersen: (on CSI: Miami) There's a lot of room for a lot of stuff on TV and obviously this is doing really well. We don't really have anything to do with it. We have only to do with our show. We don't have any time to see that show. We don't have time to really understand it. It shoots some place else. It's always nice to be the only guys on the block. There's just a lot more guys on the block now.
William Petersen: Since the start, we wanted to make sure [CSI] didn't tilt over into a soap thing If the show does go eight or nine years, if we do stuff in year two or three, what are going to do in year five or six? A lot of time shows will do something to get ratings and they'll have some big moment between two characters where they kiss, then you're stuck and [the writers] never know what to do with them.
William Petersen: (On Grissom being enigmatic) I like that, and that's intentional. I also think it's within the character of Grissom. It had less to do with me than it has to do with me believing what Grissom wants, which is, he's not somebody who's comfortable having a beer with his guys after work or knowing that this gal in the office likes him.
William Petersen: Grissom comes from a place where we know he had a deaf mother, he was raised in a silent household, on some level, had a father who potentially was not around and he learned what he knew by himself in the back yard, with bugs and animals. He's not comfortable being a supervisor and that's his problem.
William Petersen: [Grissom] is a conflicted individual, that's all I want, because that's true and that's normal.
William Petersen: Well, all of the real guys we've met with who do [forensics] for real, they're an interesting breed of cat. They do things that normal people would not do... Actually during the course of playing [Grissom], I've been able to do things I wouldn't do. I've been able to have spiders crawl on me, you know, tarantulas, and all kinds of blood, gore and guts that I don't think that I normally would have, just because of being able to be Grissom.
William Petersen: When we first started the show (CSI), CBS was very concerned about what we would show, and what we wouldn't show. I remember taking shots of maggots out of the pilot episode, because the network kept saying 'we got to get rid of the maggots. Nobody's going to watch the show.' So we reduced it down to a very specific and important maggot.
William Petersen: (on CSI spin-offs) I just think that it went too fast. There wasn't enough time for us to really make, to possibly make, these shows different than our show.
William Petersen: (on Gil Grissom and Sara Sidle's romance on CSI) I think they've been very careful, because it's obviously a very dicey situation at work if this was a relationship that was uncovered, and yet, they found themselves together on some levels. We don't know what levels for sure, you know? But they obviously always have been interested in each other. And there's an intimacy there. We just thought it was time for the audience to see that there is an intimacy there.
William Petersen: (on Grissom in the 7th season) Now he's having to supervise every death encounter that happens in Las Vegas. And it's daunting. As anyone's job is as they grow older and as they become more proficient, it becomes more daunting. It's more daunting for me to do the seventh season of CSI than it was to do the first, oddly enough.
William Petersen: (On Grissom's beard) The beard is here because I got tired of shaving and Grissom, subsequently, got tired of shaving. Grissom, like any other 50-year-old man, is going through a series of mid-life changes. Who knows, he may start drinking.
William Petersen: (on kissing scenes with Jorja Fox) We'd love to kiss but the network would have to cough up some more money for that. Tongue would cost more.
William Petersen: I've never been in this business for the recognition or the awards. I just want to do good work, grab a decent paycheck, and move onto the next job.
William Petersen: (on his post CSI plans) Theater in Chicago will always be my first love. It started careers for me and about 50 of my friends. We all love coming back. As soon as the TV show is over, I'll be back in Chicago, doing live theater.
William Petersen: (on his role as Will Graham in Manhunter) It took me two months to get that part. I mean, who the hell was I? I wasn't going to sell that picture.
William Petersen: (concerning seeing the Marlon Brando movie Last Tango in Paris) It was the first time that I understood that acting was an art form. It was not Clint Eastwood on a horse, Bob Hope in a road movie. It was not Don Knotts in The Incredible Mr. Limpet. These are favorite movies of mine, too. But when I sat in Last Tango in Paris, the light bulb went on. To this day, Brando is the one I want to meet, and the one I'm terrified to meet.
William Petersen: (On CSI as of February 2006) The show can go on without me, and probably will, but I want to come back to act in Chicago. My wife and I just bought a condo downtown, and I want to do theater.
William Petersen: (on CSI spinoffs) I thought the Miami version came too soon and that we should have taken the time to make it something different. It was just an attempt to duplicate. But Crossing Jordan came out a year after us, and Jerry Bruckheimer knew there would be others. Why should we let them steal our audience? I understand the move from a business sense, and the profits have been astronomical.
William Petersen: (on CSI spinoffs) They pulled our show apart. Anthony [Zuiker, CSI creator] is now with CSI: NY full time. We have to fight to keep our writers, producers, even our best postproduction people. I wish they'd just make our show better.
William Petersen: If I could change on thing about myself, I would: Have better knees. Mine are shot because of injuries. You're only as good as your legs, whether you're an athlete or an actor.
William Petersen: Now I'm seen by more people in one episode than I was in 20 years of theatre and movies. It's gratifying to have an impact on 25 million people a night, but I can say goodbye to my lunch-pail life as a working actor. I'm scared I might be a celebrity.
William Petersen: Sure, I always chose rebels to identify with - I still do - but to me a rebel isn't so much someone who breaks the law as someone who goes against the odds.
William Petersen: Basically, we are a whole world of people desperately trying to figure out what is the dark side of our natures and how much can we explore without becoming something else.
William Petersen: I want to live and work in Chicago for the rest of my life. You know when you were growing up and you wanted to become president? What I want now is to be mayor of this damned town in ten years.
William Petersen: I wonder how many women would want to wallow around in maggot farms at night...because that's really all Grissom could give them. Women think, 'Boy, could I make improvements on this guy,' and of course Grissom is scared to death of any improvements being made.
William Petersen: If I stayed a football player, my career would have been over 20 years ago. As it is, my knees are shot. I found I got the same good feeling in acting that I had in sports, but I found I could have a more profound impact on people.
William Petersen: One of the things I love about theater, one of the reasons I'll never give it up, is that it's fifty percent the audience's responsibility.
William Petersen: Corporate Hollywood thinks I'm a geek to go back and do theater. They don't understand why I don't want to be a movie star, why I'm not pursuing Mel Gibson's roles.