Born in Flint in 1941, Sinclair rose to prominence as a poet known for his radical politics. In the 1960s, he became manager of Detroit rock band MC5, booking them as a house band of sorts at the former Grande Ballroom, where they recorded their landmark album Kick Out the Jams. (His wife, Leni Sinclair, was a notable photographer of the scene.) In 1968, under Sinclair’s management, the MC5 performed for the massive rally outside of the chaotic Democratic National Convention in Chicago protesting the Vietnam War.
Sinclair was also a founding member of the White Panther Party, an anti-racist socialist group aligned with the Black Panthers.
In 1969, Sinclair was sentenced to ten years in prison after offering two joints to a woman who was an undercover cop. The severity of the sentence sparked protests that inspired John Lennon to write a song called “John Sinclair” and sparked Ann Arbor’s annual Hash Bash, a rally where attendees smoked pot openly on the University of Michigan campus that eventually evolved into the heart of the movement to decriminalize and legalize cannabis in the state.