He had memorable roles in numerous cult favorites, including John Carpenter's films The Thing (as Childs) and They Live(as Armitage), the Riddick films Pitch Black and The Chronicles of Riddick (as the Imam), General Kimsey in Armageddon, King in Oliver Stone's Platoon, and Big Tim in Darren Aronofsky's Requiem for a Dream. David starred as Elroy Patashnik in the sixth season of the comedy series, Community. In 2016, he began starring as Bishop James Greenleaf in the Oprah Winfrey Network drama series, Greenleaf.
His Emmy Award-winning voice-over career includes work as the narrator of numerous Ken Burns films such as The War. Characters that he has voiced include the Arbiter Thel 'Vadam in Halo 2, Halo 3 and Halo 5, Goliath on the Disney series Gargoyles, Spawn/Al Simmons on Todd McFarlane's Spawn which aired on HBO, David Anderson in the Mass Effectseries, the Decepticon Barricade in Transformers: The Game, Julius Little in Saints Row, Saints Row 2, and Saints Row IV (as well as making a major guest appearance in the last game voicing himself), Sgt. Foley in Call of Duty: Modern Warfare 2, Dr. Facilier in The Princess and the Frog, the Flame King in Adventure Time, and Chaos in the English versions of Dissidia Final Fantasy, Dissidia 012 Final Fantasy and Solovar in The Flash.