Keith had an early supporting role in the prison film Brubaker. He had a supporting role in The Rose, starring Bette Midler, and later co-starred with Richard Gere in An Officer and a Gentleman. Keith played a local thug in The Great Santini, starred in The Lords of Discipline and White of the Eye, and held a prominent supporting role in U-571 opposite Matthew McConaughey. He played opposite child-star Drew Barrymore in the 1984 hit Firestarter and Brooke Shields in 1992's Running Wild. Keith played Elvis Presley in the 1988 film Heartbreak Hotel.
He directed The Curse and The Further Adventures of Tennessee Buck (in which he also starred). He appeared in the 1995 film The Indian in the Cupboard as the cowboy "Boo-Hoo" Boone. He played the leading role of Nate Springfield in the 2003 film Hangman's Curse. He also co-starred in The Class, an American sitcom, as Yonk Allen, a retired professional football player. Other roles include parts in Daredevil and the 2002 TV movie Carrie. He appeared in the 2004 film Raise Your Voice starring Hilary Duff, and the 2006 film Expiration Date. He has appeared on many television shows, including NCIS, Law & Order: Special Victims Unit, Law & Order: Criminal Intent, CSI: Miami and High Incident.