Chef was voiced by legendary soul musician, Isaac Hayes. Show creators Trey Parker and Matt Stone originally came up with the idea for a deep-voiced character while tripping on LSD in college. They would do the voices to each other, but in order to avoid criticism from having a white person doing a black character, they sought a black voice actor for the role. Both were surprised when Hayes accepted the part.
Chef was a prominent side character, and one of the main adults, in the first nine seasons of South Park. He is the first character aside from the main boys seen in the pilot episode, "Cartman Gets An Anal Probe." Along with Token Black, Chef is one of the few black people in South Park. His real name is Jerome McElroy. Owing to his popularity in the show's early run, one of the first South Park games was named after him (Chef's Luv Shack).
While the boys typically ignore their parents and teachers, Chef was the only adult they looked up to and sought advice from. Most of the questions they would ask him were about sex. As other adults in South Park are often even more irrational and ill-informed than the children, Chef was usually portrayed as one of the few level heads in town. In the season one episode Pink-eye, Chef was the first to realize the town was being overrun with zombies, not people infected with pink-eye. In the episode "Proper Condom Use," he is the only one who recognizes the fourth graders are too young for a sex-ed talk. Early episodes had Chef teaching the kids lessons through songs, but this trope was seen less and less as the show went on.
Chef is one of the few characters to be fully written off of the show. This came after voice actor Isaac Hayes quit after the ninth season. The impetus was supposedly the controversial episode "Trapped in the Closet," which mocks Scientology and celebrities like Tom Cruise and John Travolta (both avowed Scientologists). Hayes was also a Scientologist, and him taking offense to the episode is usually listed as the cause for his departure, but in 2016 his son Isaac Hayes III said the decision was made by his father's entourage of Scientologists. A statement was released under Hayes' name stating the "Closet" episode led to him leaving, but there is doubt as to whether or not Hayes actually authored the statement.
The show responded by permanently killing off the Chef character in the season ten premiere "The Return of Chef." In 2007, Hayes stated he left the show because he was not getting paid enough, and in 2008 he said he was no longer on good terms with Matt and Trey. Isaac Hayes died later that year. The first episode to air since his passing, "The China Probrem," was dedicated to him.