[1] Roos was born in upstate New York into a conservative Roman Catholic family of mostly Irish descent.

Roos wrote for The Colbys, Nightingales, and other TV shows, before his spec scripts led to feature film writing assignments.

His first major film was 1992's Academy Award-nominated Love Field, an interracial drama starring Michelle Pfeiffer and Dennis Haysbert.

[3] Roos's work as the writer of the film Single White Female has earned him a permanent space in Hollywood movie trivia, since that title has entered the lexicon[citation needed] in reference to the film's psychopathic lead character who begins to take on her roommate's identity.

Roos is well known for his work writing strong and engaging female characters,[citation needed] a skill that has also been useful in his film direction, leading to Independent Spirit Award nominations for actors Lisa Kudrow, Christina Ricci and Maggie Gyllenhaal.