Nathan Fillion is a Canadian-American actor known to TV audiences for his role as Captain Malcolm "Mal" Reynolds in the short-lived but well-loved Joss Whedon series Firefly (2002-03). Fillion got his start in New York, spending three years on the daytime soap opera One Life to Live in the late 1990s. He moved to Los Angeles to further his screen career, and after small roles in the movies -- including Steven Spielberg's Saving Private Ryan (1998) -- he became a regular on Two Guys, a Girl and a Pizza Place (1998-2001, with Ryan Reynolds). As the lead in Firefly, Fillion perfected his light-hearted, reluctant hero persona, which he has since put to good use in movies and TV series. His feature films include Serenity (2005, based on Firefly) and Waitress (2007, starring Keri Russell), and his TV credits include Desperate Housewives (the fourth season, 2007-08) and, as the title character, ABC's Castle, which began in 2009.

Mostly known for his roles in light comedy, Fillion played a villain, Caleb, in the final season of Whedon's series Buffy the Vampire Slayer... He also appeared as Captain Hammer in Joss Whedon's internet musical, Dr. Horrible's Sing-Along Blog (2009).