Sean's theater credits include the following productions: Doors, Yerma, Berlin, Berlin, Over the Tavern, Part II, Book of the Night, Severity's Mistress, and Into the Woods.
While filming for the TV series Firefly, Sean was notorious for calling actress Summer Glau (who played his sister, River Tam) by her real first name rather than by her character's name.
Sean: (On his favorite memory of Firefly and Serenity director, Joss Whedon) My favorite moment – and he wasn't on the set - but we were shooting the series and I just remember the time when his first child was born. That's probably – that sort of epitomizes to me how much of a family I feel with these people. To just be on set and get word that Joss had his first child and how moving that was.
Sean Maher: (about making Serenity) There was a wonderful feeling of redemption, because we've come back with these people, this great reunion, and there was a wonderful energy.
Sean Maher: Initially, I was turned off by the idea of [being in a science fiction project] because I wouldn't want to do science fiction. But it's not really science fiction. It's Joss's version. It almost feels like a post-apocalyptic Western.