Thomas Duff

Thomas Milton Duff (born December 31, 1956) His mother is Bobbie Baggett Duff and his father is Ernest Duff, a lawyer and businessman on the side. He has three siblings, James Duff, Stephen Duff, and Jane Duff Thomley. In 1979, Duff graduated with a bachelor's degree in business administration from the University of Southern Mississippi.

Career Ernest Duff, Thomas's father, founded Southern Tire Mart in 1973. Thomas and his brother James both worked there as teenagers and assumed control of the struggling company in 1983, later selling it in 1998 to Tire Distribution Systems. By 2025, Southern Tire Mart's revenues had grown to exceed $4 billion, making it the nation's largest truck tire dealer and retread manufacturer. Since 2009, the brothers have been the only members of the Forbes 400 list from Mississippi with the exception of 2024, where they were not present. Together, they remain the wealthiest individuals in Mississippi.

Duff was subject to a lawsuit that accused him of Paycheck Protection Program fraud in 2024. The lawsuit alleged that Southern Tire Mart was claimed to be a small business with fewer employees than was actually the case in order to access federal funds. The plaintiffs voluntarily retracted their lawsuit on May 21, 2026.

Politics A major contributor to Republican campaigns in Mississippi, Duff has supported Republican figures such as Governor Tate Reeves, to whose campaigns he has contributed regularly since 2011, and Donald Trump in the 2020 and 2024 presidential elections.

Duff formed a political action committee (PAC) in December 2024 to help elect Republicans in 2025 municipal and special legislative elections. He is considering a run for Mississippi governor in 2027. He attended the Neshoba County Fair, the state's preeminent political gathering, in 2024.

Philanthropy He and his brother have made contributions totaling around $50 million to the University of Southern Mississippi, the University of Mississippi, and Mississippi State University.