Robert Knepper's films include Good Night, and Good Luck, Hostage, Species III, Swatters and Love & Sex. His additional feature credits include Young Guns II, Renegades, That's Life! and Wild Thing.

On television, Knepper has had recurring roles on the series Carnivale, Thieves, Haunted and Presidio Med. He has guest-starred on series such as ER, The West Wing and Getting Out. Knepper also starred in the miniseries Jackie, Ethel, Joan: The Women of Camelot.

Knepper owes his acting career in large part to his mother, who, when he was a child, worked in the props department for a community theater in Freemont, Ohio. This involvement sparked Knepper's interest in the arts, leading him to work in community theater and high school productions. He went on to study drama at Northwestern University.