Early life

Gilliam graduated from State University of New York at Purchase in 1990.

Career

Gilliam's film career has spanned from the early 90s to today; starring in award-winning films such as "Still Alice". His other film credits include Private Sugar Watkins in the 1997 action film Starship Troopers and Sergeant Steven Altameyer in the 1996 film Courage Under Fire. Gilliam has had a number of recurring roles on television, including during the seventh season of The Cosby Show as Aaron Dexter, boyfriend of Erika Alexander's character, and as Alan Deaton on Teen Wolf. His most prominent role, however, has been on The Wire. In 2008, he attracted attention for criticizing the show being overlooked for Emmy nominations despite its critical success. He has also had a number of guest roles in other shows such as CSI: Miami, Nurse Jackie, Skins, Person of Interest, and The Good Wife. He played Clayton Hughes on Oz.

Gilliam has also acted on stage, playing Prince Edward in a 1993 production of Richard III, and as the lead in the Commonwealth Shakespeare Company's 2010 and 2011 productions of Othello at the Houston Shakespeare Festival, directed by his wife Leah C. Gardiner. He also played Antony in Antony and Cleopatra for the Houston Shakespeare Festival, also directed by his wife. He has stated that he prefers acting on the stage although he loves his work in film and television: "Acting for the stage is a lot more fun to do. There is instant communication with the audience. An actor can tell whether or not he or she is connecting with an audience or whether they understand what's going on." In May 2014, Gilliam was cast as Gabriel Stokes in the fifth season of AMC's The Walking Dead. Along with Chad Coleman and Lawrence Gilliard, Jr., he is the third The Wire alum to join the series. He also continues to play Dr. Deaton in Teen Wolf for MTV.

Filmography

Film

Year	Title	Role	Notes
1993	Joey Breaker	Jeremy Breaker
1993	Mr. Wonderful	ER Doctor
1994	The Hardest Part	Derek	Short film
1995	Jefferson in Paris	James Hemings
1996	Courage Under Fire	Altameyer
1997	Starship Troopers	Sugar Watkins
1997	Tar	Tyrone
2000	Punks	Marcus
2002	Personal Velocity: Three Portraits	Vincent
2005	The Great Wonderful	Clayton	Segment: "Emme's Story"
2008	Sympathetic Details	Raymond
2009	The People v. Leo Frank	Jim Conley
2009	Did You Hear About the Morgans?	U.S. Marshal Lasky
2010	Betrayed	Roger Waite	Short film
2011	Stake Out: Atlantic Salmon	Rivers	Short film
2014	Still Alice	Frederic Johnson
2015	Police State	Officer Grady

Television

Year	Title	Role	Notes
1990-91	The Cosby Show	Aaron Dexter	3 episodes
1992	Law & Order	Babatunde Amoda	Episode: "Consultation"
1992	In the Eyes of a Stranger		Television film
1994	Assault at West Point: The Court-Martial of Johnson Whittaker	Cadet Johnson C. Whittaker	Television film
1999-2001	Oz	Clayton Hughes	17 episodes
2002-08	The Wire	Ellis Carver	60 episodes
2005	Law & Order: Trial by Jury	A.D.A. Terence Wright	4 episodes
2007	The Bronx is Burning	Paul Blair	Episode: "Time for a Change?"
2007-08	Law & Order: Criminal Intent	Detective Daniels	4 episodes
2009	Damages	Mark Waters	Episode: "I Knew Your Pig"
2009	CSI: Miami	Aaron Nolan	Episode: "Flight Risk"
2009	Mercy	Police Officer	Episode: "Destiny, Meet My Daughter, Veronica"
2010	Nurse Jackie	Dr. Lindsey	Episode: "Candyland"
2010	Law & Order	Michael's Attorney	Episode: "Immortal"
2011	The Good Wife	Jacob Rickter	Episode: "Closing Arguments"
2011	Svetlana	Tomas	Episode: "Milking It"
2011-present	Teen Wolf	Dr. Alan Deaton	Recurring role; 31 episodes
2012	Person of Interest	Detective Des Franklin	Episode: "Identity Crisis"
2012	Homeland	Chapman	Episode: "A Gettysburg Address"
2013	Criminal Minds	Lyle Johnson	Episode: "Strange Fruit"
2014-present	The Walking Dead	Gabriel Stokes	Season 5-present (main role; 19 episodes)
2016	Elementary	Dr. Ira Wallace	Episode: "Ready or Not"

[ Source: Wikipedia ]