Born Joseph Hill Whedon, Joss spent his childhood in Manhattan before attending an all-boys high school in England. Upon graduation he returned to the United States and attended Connecticut's Wesleyan University where he received a degree in Film Studies. He then moved to Los Angeles, and after a year of being unable to find work in the industry he landed a job as a writer and story editor for the television show Roseanne. He had been seeking a career in movies, but this job was familiar to him because his father and grandfather had both written for the medium, making Joss arguably the world's first third generation television writer. It was during this time that he met Kai Cole, the woman who he later married.
After a year working on Roseanne, and writing and co-producing a number of episodes of Parenthood, Joss sold his first movie script for Buffy the Vampire Slayer. Despite negative reviews and modest box office, the film went on to become a cult hit and Joss found himself much in demand as a writer and "script doctor" in Hollywood. Often uncredited, Joss wrote or worked on drafts of screenplays for such films as Speed, X-Men, and Alien: Resurrection. He was nominated for an Academy Award for his work on Toy Story.
In 1997, Joss was approached by the brand new Warner Brothers Network (The WB) who requested that he submit some ideas for new programs. He had always been disappointed by the way his first film script was handled, so he suggested a TV version of Buffy the Vampire Slayer under the condition that he be allowed total creative control. The network agreed, and soon Buffy was being widely praised as one of the best shows on television. In 1999, Whedon launched the first spin-off of Buffy called Angel. It, too, was praised by fans and critics and quickly developed its own devoted following. Buffy the Vampire Slayer ran for seven seasons before the cast and creators decided to end the series. Angel however, was cancelled after five seasons, prompting one of the largest fan reactions in television history. Despite the massive efforts, however, the show did not return.
In 2002, Joss moved to the larger networks with a new series called Firefly on Fox. The series was a futuristic science fiction with a western flair and was instantly hailed by critics and fans alike as one of the most original shows in years. Despite the positive reviews, however, Firefly never found an audience and was cancelled after only eleven episodes. Many blamed the network who gave the series an historically poor timeslot, did very little advertising, and aired the episodes out of order with the pilot as the last episode ever aired. Shortly after the series' cancellation was announced, Joss and Kai had a son, Arden, on December 18, 2002.
Due to incredible sales of the Firefly DVD set and Joss' dogged persistence, Universal Pictures eventually offered him the chance to try his series on the big screen. Joss was given free rein to write and direct the silver screen adaptation of Firefly called Serenity which opened on September 30, 2005. During this time he was also tapped to write and direct a feature film version of Wonder Woman, which was planned to be released in 2006. This project fell through, but Joss was soon announced as the Director of Marvel Comics' super group film The Avengers, one of the biggest comic book film adaptations to date.
During the post-Firefly period, Joss also expanded into the realm of one of his early inspirations, comic books. He has written a twelve-issue run of the new series Astonishing X-Men which was an instant critical and sales hit. Over the years he has also contributed to a number of other comic book projects involving his characters Buffy and Angel, including continuations of both series into further official "seasons" and a mini-series called Fray about a Slayer in the future of the Buffy world.