Floyd was born in Brooklyn, NY, in 1947, and moved to Long Beach, NY, ten years later. He graduated from Franklin & Marshall College with a B.A. in English, and completed an M.A. in English at Southern Illinois University, where he studied with the Irish poet Thomas Kinsella. From 1972 until becoming disabled by viral-borne brain damage in 1988, Floyd worked in the field of public policy in Illinois, Washington, and Oregon. He began publishing poetry in 1970, fiction in 1975, and essays in 1990. His work has appeared in many major literary journals in the US and abroad. His twenty-one books have won wide acclaim and numerous awards, and are included in many high school and college curricula. In May, 2006 he received an honorary Doctor of Humane Letters degree from Franklin & Marshall College.
An Oregonian since 1984, Floyd moved from Portland to rural Amity when he married Beverly Hallberg in 1993. They lived in a cedar yurt in the middle of twenty hilly acres of woods for 13 years before moving back to Portland. Beverly is a birder and landscape painter whose light-filled works cross between impressionistic and abstracted styles. Her art graces the covers of several of Floyd's books.
Floyd's daughter is the nonfiction writer . Her book, The Immortal Life of Henrietta Lacks, was published by Crown Books in February, 2010 and became a 9 year NY Times bestseller. It was also the winner of the Heartland Prize and Wellcome Trust Book Prize, and has been translated into nearly thirty languages. The emmy-nominated movie adaptation premiered in 2017 on HBO starring Oprah Winfrey and Rose Byrne. Floyd and Rebecca co-edited The Best American Science Writing 2011. Floyd's stepson, Matthew Coale, lives in Spokane, Washington.