While studying at the Neighborhood Playhouse, Britton (then Womack) made her NY theatrical debut in Caroline Kava's The Early Girl at The Courtyard Playhouse. Britton played seasoned prostitute, Laurel, opposite then unknown television and radio personality Cooper Lawrence, who played Joan. Britton's performance, while well received, nearly got her ousted from the Neighborhood Playhouse program, which prohibited students from taking professional employment during their course of study. After graduating, Britton spent two more years working in off-Broadway theatre productions. She moved to Los Angeles after the success of "The Brothers McMullen". In her free time, Britton, who resides in both New York and Los Angeles, enjoys hiking, yoga, and doing volunteer work.

Britton had a recurring role on 24, during its fifth season as Diane Huxley, the landlady of protagonist Jack Bauer (Kiefer Sutherland). She co-starred in the indie-thriller The Last Winter in 2006.