He was born on January 23, 1962, received his B.A. from Auburn University, and J.D. from the Cumberland School of Law of Samford University.
He is married to Tanya McGough Guin, who is a principal in the Walker County School System, and is the father of James Kenneth Guin, III (J.K.) and Emma Grace Guin.
Representative Guin works as an attorney and serves as a Lay Leader at First United Methodist Church of Carbon Hill. He is also Chairman of Trustees for the Southwest District of the United Methodist Church.
He is a member of the Board of Directors of the State Legislative Leader Foundation, Democratic Legislative Campaign Committee, and State Advisory Board of the Democratic Leadership Council.