Whitlock was a longtime ensemble member of the Atlantic Theater Company.

Isiah Whitlock Jr., a prolific screen and stage actor, has died following a short illness at the age of 71.
Whitlock was a longtime collaborator of the writer/director Spike Lee, appearing in his films She Hate Me, 25th Hour, Red Hook Summer, Chi-Raq, BlacKkKlansman, and Da 5 Bloods. In those moves, and throughout his career, he developed and used an indelible catchphrase — exaggerating the pronunciation of shit as Sheeeeeeeee-it, which has become renowned.
On screen, Whitlock was best known for playing corrupt senator Clay Davis in HBO’s The Wire. His long list of credits ranged from Goodfellas to Law & Order to Pieces of April to Veep. His last TV role wasas the Chief of Police opposite Uzo Aduba on Netflix’s The Residence.
A longtime ensemble member of off-Broadway’s Atlantic Theater Company, Whitlock starred there several plays, including Farragut North. Before becoming a regular on screen, he worked at New York Theatre Workshop, Signature, Primary Stages, and various other off-Broadway theaters. He was a 2002 Lucille Lortel Award nominee for the play Four.
On Broadway, Whitlock understudied the role of Joe Mott in the Kevin Spacey-led Iceman Cometh and was in the ensemble of the Dustin Hoffman Merchant of Venice. His Broadway debut was in Larry Gelbart’s Mastergate.