William Roscoe Mercer (1927–2000), also known as Rosko, was an American announcer, commercial voice over specialist and disc jockey (DJ).
His first job for a large media market radio station came in 1965, when he was a DJ on KBLA 1500 AM in Burbank, California.
Mercer provided voiceovers for several films that Jim Henson created during the early days of Sesame Street.
Rosco provided the sleeve notes for the Sly & the Family Stone album, Life that was released in 1968.
[3] In the early 1980s, he joined 92.3 WKTU in New York during its disco music era, for an evening program.