Derek Morgan is a fictional character on the CBS crime drama Criminal Minds, portrayed by Emmy Award winner Shemar Moore. Morgan specializes in fixations and obsessive behaviors. He is a Supervisory Special Agent of the FBI's Behavioral Analysis Unit, (although has served as interim unit chief for Aaron Hotchner), and has appeared from the series' pilot episode "Extreme Aggressor", which was originally broadcast on September 22, 2005. Before he left in season 11, he was one of only three main characters to appear since the first season as "starring", while also becoming the only character to appear in all episodes.