b. 3 May 1926, Chicago, Illinois, USA. After graduating from DePaul University O’Horgan worked in the theatre and in New York in the early 60s was involved with several off-Broadway productions. From the late 60s onwards, he directed some Broadway and off-Broadway smash hit musicals. His success began with Hair (1968), which ran for 1, 742 performances and brought him a Tony Award nomination as Best Director Of A Musical. That same year saw him win a Drama Desk Award as Outstanding Director for Futz!; he also won an award for directing Tom Paine, and was named by Newsweek as Theatrical Director Of The Year. In 1971 he directed Lenny (1971), for which he composed the incidental music and again won a Drama Desk Award as Outstanding Director. Another huge musical success came when he wrote the book for and directed Jesus Christ Superstar (1971), music and lyrics by Andrew Lloyd Webber and Tim Rice, and that same year he conceived, produced and directed Inner City. Much less successful were the musical, Dude (1972) and the play, The Leaf People (1975). A brief revival of Hair came in October 1977, followed by a similarly short run for a revival of Jesus Christ Superstar a few weeks later. He directed and wrote the incidental music for I Won’t Dance, a one-day show in May 1981, directed a revival of the musical The Three Musketeers, one week in 1984, and wrote the music for and was slated to direct Senator Joe, which never made it to its scheduled January 1989 opening.
During the 60s, O’Horgan’s music was used in the films A Touch Of Greatness (1964), Babo 73 (1964), Sweet Smell Of Sex (1965), Chafed Elbows (1966), Boxiganga (1967), which he also directed as he did Futz! (1969). He also had small onscreen parts in some of these films. In the 70s he wrote the music and conducted the studio orchestra for Alex In Wonderland (1970), directed Rhinoceros (1971), and composed and was musical director for the Danish television production Sårede Filoktet (1974). He also conceived and adapted for the stage a 1978 production based upon the Beatles’ Sgt. Pepper’s Lonely Hearts Club Band.