Harold Joseph Lennix III is an American actor. He is known for his roles as Terrence "Dresser" Williams in the Robert Townsend film The Five Heartbeats (1991) and as Boyd Langton in the science-fiction series Dollhouse. Lennix co-starred as Harold Cooper, assistant director of the FBI Counterterrorism Division, on the NBC drama The Blacklist. Lennix also played J'onn J'onzz/Calvin Swanwick/Martian Manhunter in the DC Extended Universe films Man of Steel, Batman v Superman: Dawn of Justice, and Zack Snyder's Justice League. He was nominated for the 2025 Tony Award for Best Actor in a Play for his role in Purpose.