First recorded by the Original Off-Broadway Cast of Hair (1967).
Hit versions by Zen (NETH #1 1968), Doug Parkinson in Focus (AUS #7 1969), The Cowsills (US #2 1969).
From the wiki: “Hair: The American Tribal Love-Rock Musical wass a Rock musical with a book and lyrics by James Rado and Gerome Ragni, and music by Galt MacDermot. The musical broke new ground in musical theater by defining the genre of ‘rock musical’, using a racially integrated cast, and inviting the audience onstage for a ‘Be-In’ finale. After an off-Broadway debut in October 1967 at Joseph Papp’s Public Theater and a subsequent run in a midtown discothèque space, the show opened on Broadway at the Biltmore Theatre on April 29, 1968 and ran for 1,750 performances. A cast album recorded by the original off-Broadway cast was released in 1967; the original Broadway cast recording, released in 1968, received a Grammy Award for Best Score from an Original Cast Show Album.
“The musical’s title song, ‘Hair’, begins as character Woof slowly croons his reason for his long hair, as tribe-mate Berger joins in singing they deem they ‘don’t know.’ They lead the tribe, singing ‘Give me a head with hair,’ ‘as long as God can grow it,’ listing what they want in a head of hair and their uses for it. A cover of ‘Hair’ became a major hit single for The Cowsills in 1969 and was their most successful charted single.”