He is best known as a member of folk-rock band the Lovin' Spoonful, where he was their drummer and later lead vocalist, the group had seven top 10 hits between 1965 and 1966.

Butler would tour and front the band, singing, playing autoharp, percussion and acoustic guitar.

In 2000 Butler would reunite with the original lineup for the final time and be inducted into the Rock and Roll Hall of Fame.

Butler was a principal member of the pop rock band the Lovin' Spoonful, founded by John Sebastian and Zal Yanovsky in 1965.

Original drummer Jan Carl was replaced by Butler after their first gig at the Night Owl in Greenwich Village.

While with the Lovin' Spoonful, Butler was given the lead vocals on the songs "You Baby", "Full Measure", "Never Going Back", "Only Pretty, What A Pity" and "Me About You".

In 1980 Butler would first reunite with the original line up of John Sebastian, Zal Yanovsky and Steve Boone, to appear in the movie One-Trick Pony.

[8][9][10] Butler was inducted into the Rock and Roll Hall of Fame as a member of the Lovin' Spoonful in 2000[11][12] and performed with the original line-up for the last time.

After the Lovin Spoonful would break up in 1969 Butler started acting, he got his first role in the 1971 rock opera Soon, playing the character of Neil.

[12][18] Butler created the role of Alaska Wolf Joe for the off-Broadway production of the Brecht-Weill social opera the Rise and Fall of the City of Mahagonny.

[21] Alongside award-winning and renowned director Marshall W. Mason and Pulitzer Prize winning playwright Lanford Wilson, Butler has written and directed numerous projects.