He has had parts in television police dramas such as New York Undercover, Homicide: Life on the Street and The Wire. He was featured on Homicide in a multi-season recurring role as fictional drug kingpin Luther Mahoney; on The Wire he plays a medical examiner.
Early in his career he had minor appearances in several Spike Lee films, such as She's Gotta Have It and Do the Right Thing. He was portrayed (as a child) by Travis Kyle Davis in the Disney Channel Original Movie The Color of Friendship, which was based on what happened when his family hosted a foreign exchange student from South Africa during the Apartheid era. (He also had a cameo in this movie playing one of Congressman Dellums' aides.) In addition, he provided the voice acting for the character "Koh the Face Stealer" in the animated Nickelodeon series Avatar: The Last Airbender, as well as the narration for "Key Constitutional Concepts", a documentary produced in 2006 by the Annenberg Foundation. In The Elder Scrolls V: Skyrim he voices Nazir, a Redguard who is part of the Dark Brotherhood.
Dellums is the son of Ron Dellums, the mayor of Oakland and former U.S. Representative from California.
In January 2013, Erik teased his Twitter followers that he may have some involvement with a future Fallout publication.