Isaac Lee Hayes, Jr. (August 20, 1942 – August 10, 2008) was the voice of Chef from 1997 until he left South Park because of the controversy surrounding "Trapped in the Closet" in 2005. Even without the controversy, his role on the show became less prominent due to the change of style (the boys learning things without the Chef character's involvement) and Hayes own deteriorating health. It has been hypothesised by his family that the Church wrote his resignation for him.
Well before leaving, Hayes made an appearance as himself in the mockumentary, Chef Aid: Behind the Menu, in which he did not know who Chef was.
In a 2007 interview, Hayes mentioned he quit because "They (Parker and Stone) didn't pay me enough... They weren't that nice."
On August 10, 2008, Hayes passed away at the age of 65 due to complications caused by a stroke and was commemorated by South Park Studios.