After being accepted as the photographer for Student Nonviolent Coordinating Committee (SNCC), Lyon was present at almost all of the major historical events during the Civil Rights Movement.

He was raised in Kew Gardens, Queens, and went on to study history and philosophy at the University of Chicago, where he graduated with a Bachelor of Arts degree in 1963.

Lyon began his involvement in the civil rights movement in 1962 when he hitch-hiked to Cairo, Illinois during a summer break after his junior year at the University of Chicago.

Lyon then decided to march to a nearby segregated swimming pool, the demonstrators knelt down to pray as the pool-goers heckled them.

[10] In September 1962, with a $300 donation by Harry Belafonte, the Student Nonviolent Coordinating Committee (SNCC) flew Lyon to Jackson and the Mississippi Delta to cover voter registration workers.

[9] After being accepted as the photographer for SNCC, Lyon was present at almost all of the major historical events during the movement capturing the moments with his camera.

His first was a study of outlaw motorcyclists in the collection The Bikeriders (1968), where Lyon photographed, traveled with and shared the lifestyle of bikers in the American Midwest from 1963 to 1967.

[17] In 1969, when Lyon returned from his work in Texas to New York City, and had no place to live, the photographer Robert Frank, famous by then for his 1958 book The Americans, took him in.

In particular, the book focuses on the case of Billy McCune, a convicted rapist whose death sentence was eventually commuted to life in prison.

In the foreword, Lyon describes McCune as a diagnosed psychotic, who one evening, while awaiting execution, "cut his penis off to the root and, placing it in a cup, passed it between the bars to the guard."

He was greatly encouraged in his photography by curator of the Art Institute of Chicago[6] Hugh Edwards, who gave Lyon two solo exhibits as a young man.