Thomas T. Irvin was born in Lula, Hall County on July 14, 1929. The Irvin family later moved to White County where they were sharecroppers. Irvin and his wife Bernice met while attending the Southeastern Fair, and they married on June 1, 1947. Irvin was elected to his first public office as a member of the Habersham County Board of Education in 1956. He later served as school board chairman and president of the Georgia School Boards Association.
A Democrat, Irvin was elected to four terms in the Georgia General Assembly as a Representative from Habersham County, where he served on the House Agriculture, Education, and Appropriations Committees and chaired the House Industrial Relations Committee and the Governor's Conference on Education. Irvin managed Lester Maddox's controversial 1966 gubernatorial campaign and would continue his involvement with Maddox serving as the Governor's Floor Leader and Executive Secretary to the Governor. Governor Maddox appointed Irvin to serve as Commissioner of Agriculture in 1969 after Commissioner Phil Campbell left to serve in the Nixon administration.
Commissioner Irvin served as Georgia's Commissioner of Agriculture from 1969 until January 2011. He was elected to his 10th and final four-year term in November 2006. Irvin holds a record as the longest-serving Commissioner of Agriculture in the United States, and the longest-serving statewide official in Georgia. Irvin and his wife now reside in Mount Airy where they are proud of their fourteen grandchildren and two great-grandchildren.