Marshall was born in 1943 to Max and Catherine Marshall in Ardmore, Oklahoma. He was raised with his brother Gary in Augusta, Kansas. With Guillian Marshall, he had three children, James, Jennifer and Morgan, and also had grandchildren. He attended Wichita State University, then left the college and went to Texas to work for a short while on a fishing boat. He left Texas to move to the Bay Area, and lived much of the rest of his life in San Francisco where he was active in the 60s scene.