Casey was born in Yonkers, NY, and was an art major at Syracuse Univ. After teaching in upstate NY, he moved to Chicago in 1962, where he held a variety of jobs but soon gravitated towards acting and writing songs.

He acted with the Chicago Stage Guild, the Old Town Players and the Kingston Mines. The Kingston Mines, the first company to suspect anyone might listen to his songs without a can of beer in his hand, staged the original production of Grease. With Jim Jacobs, he wrote Island of the Lost Coeds, a musical satire of the B-movies of the 1950s.

Warren Casey died of AIDS related desease in Chicago at the age of 53.