Peter Stampfel and Steve Weber, the original members of the Holy Modal Rounders, had joined the influential underground rock band the Fugs in 1965.

[2] Stampfel subsequently formed a rock band, the Moray Eels, with his girlfriend Antonia Duren and drummer Sam Shepard (who was already a noted playwright).

Despite Stampfel's warning of Weber's reluctance to rehearse without enforcement, the band ultimately entered the studio in June 1967 without having played together in about two years and without an idea of what they would record.

Mark Deming of AllMusic retrospectively noted in comparison to the duo's first two album that "Indian War Whoop is a thoroughly bizarre listening experience" with "neo-psychedelic fiddle-and-guitar freakouts and free-form (and often radically altered) interpretations of traditional folk tunes.

"[1] He concluded that "its buoyant good humor and chemically-altered enthusiasm remains effective, even when the Rounders' reckless pursuit of inner space sounds like it was more fun to create than to observe on record."