William "Rosko" Mercer (1927-2000) was a prominent and popular disc jockey in New York City. He provided voices and narration for several segments Jim Henson created for Sesame Street. These include "The Queen of Six," "The King of Eight," and the Scanimate Films (as Limbo).
Mercer began his disc jockey career in various places beginning in the late 1940s and early fifties. He joined New York station WINS as their first black announcer, and then shifted to California as a rock and roll DJ, where he began using "Rosko" (based on his actual middle name, Roscoe) as his air name. He returned to New York City, where his outspoken stances on restrictive station formatting and against the Vietnam War (and war in general) led to firings or resignations. He read poetry on the air, narrated albums combining political commentary with music, and released singles such as "Peacemaker," consisting of smooth rhythmic recitation.
Mercer moved to France in 1970 and broadcast for the Voice of America. Back in New York in the 1980s, he became the voice of CBS Sports on radio and selected television until 2000.