Emmett Grogan was a founder of the Diggers in the Haight-Ashbury district of San Francisco, California. The Diggers took their name from the English Diggers (1649-1650), a radical movement opposed to feudalism, the Church of England and the British Crown.

The San Francisco Diggers were a legendary group that evolved out of two radical traditions that thrived in the Bay Area in the mid-1960s: the bohemian/underground art/theater scene, and the New Left/civil rights/peace movement. The Diggers combined street theater, direct action, and art happenings in their social agenda of creating a Free City. Their most famous activities revolved around distributing free food ("Free because it's yours!") every day in the park, and distributing "surplus energy" at a series of Free Stores (where everything was free for the taking.)

The Diggers coined various slogans that worked their way into the counterculture and even into the larger society — "Do your own thing" and "Today is the first day of the rest of your life" being the most recognizable. The Diggers ultimately inspired Abbie Hoffman to undertake a similar venture on the Lower East Side of New York City during the mid-1960s. The Diggers of the 1960s also inspired present-day Food Not Bombs groups who distribute free food to the hungry.

Grogan's penchant for personal myth making and distrust of the mainstream media resulted in few details of his life being reliably recorded. His 1972 autobiography, Ringolevio (A life played for keeps), is filled with embellishments and large portions of his pre-Digger life appear to be outright fabrications. This flexibility with the truth was part of Grogan's larger social and political agenda, and was meant to further Digger ideals. Grogan was also the author of Final Score, a fictional crime novel.

Emmett Grogan sang back-up with Ramblin' Jack Elliott on "Mr. Tambourine Man" written by Bob Dylan. Dylan dedicated his 1978 album Street Legal to Grogan.

On April 6, 1978, 35-year-old Emmett Grogan was found dead on an F Train subway car in New York City, the victim of a heart attack possibly induced by chronic heroin use. This has been disputed and alternative theories exist.