Thomas earned a bachelor's degree from the University of Georgia and his law degree from the Walter F. George School of Law at Mercer University. He lives in Vidalia his wife.

Thomas previously worked at the law firm of Tom A. Peterson IV, LLC. His practice includes criminal defense, civil litigation, real estate transactions, and workers' compensation.

Thomas Alexander Peterson IV was appointed as the Toombs County solicitor general in June 2023. He was previously the city attorney for Lyons County and the county attorney for neighboring Tattnall County. He has served on the Advisory Committee for the U.S. District Court for the Southern District of Georgia since 2013.