Billionaire Profile
Thomas Duff
Global Rank
#980

Image: Public domain | via Wikimedia Commons

Thomas Duff

CEO, Southern Tire Mart
US
Real-Time Net Worth
$4.1B
As of December 2025
Age
68
Source
Tires, diversified
Industry
diversified
Citizenship
US

Biography

Thomas Duff is a 68-year-old American billionaire businessman and philanthropist. His wealth source is tires and diversified businesses. Alongside his brother, James Duff, he co-owns Southern Tire Mart, the largest truck tire dealer and retread manufacturer in the United States, and Duff Capital Investors, the largest privately owned business in Mississippi. Duff's career includes co-founding Duff Capital Investors, a holding company with total revenue of $6 billion from over 20 businesses. He also serves on the Mississippi Power Board of Directors and is involved in philanthropy, including contributions to Mississippi universities. He is also a major contributor to Republican campaigns in Mississippi. Duff is considering a run for Mississippi governor in 2027.

Wealth Over Time

In-Depth Profile

Early Life

Thomas Milton Duff was born on December 31, 1956, and raised in Columbia, Mississippi. He graduated from Columbia High School in 1974 and earned a bachelor's degree in business administration from the University of Southern Mississippi in 1979.

Rise to Success

Duff's career began in the tire industry. His father, Ernest Duff, founded Southern Tire Mart in 1973. Thomas and his brother James took control of the struggling company in 1983. They later sold it in 1998 but bought it back in 2003. Under their leadership, Southern Tire Mart grew to become the largest truck tire dealer and retread manufacturer in the United States, with revenues exceeding $4 billion by 2025.

Key Business Strategies

Key to the Duff brothers' success was their ability to identify and capitalize on opportunities. They expanded Southern Tire Mart and diversified their investments through Duff Capital Investors. This holding company includes over 20 businesses in various sectors, including trucking, construction, and automotive dealerships. They have also shown a knack for turning around failing companies.

Philanthropy

Thomas Duff and his brother James have a history of philanthropy, particularly supporting higher education in Mississippi. They have pledged a total of around $50 million to the University of Southern Mississippi, the University of Mississippi, and Mississippi State University.

Career Milestones

1973

Southern Tire Mart Founded

Ernest Duff founded Southern Tire Mart, the company that would become the cornerstone of the family's wealth.

1979

Graduated from University

Thomas Duff earned a bachelor's degree in business administration from the University of Southern Mississippi.

1983

Took over Southern Tire Mart

Thomas and his brother James took control of the struggling Southern Tire Mart.

2003

Bought back Southern Tire Mart

Thomas and James Duff repurchased Southern Tire Mart.

2007

Founded Duff Capital Investors

Thomas and his brother James co-founded Duff Capital Investors, a holding company.

2015

IHL Board of Trustees

Appointed to the board of trustees for the Mississippi Institutions of Higher Learning (IHL).

2024

Formed Duff PAC

Launched a political action committee.

Philanthropy & Social Impact

Education

University of Southern Mississippi

$50M

Made contributions totaling around $50 million to the University of Southern Mississippi, the University of Mississippi, and Mississippi State University.

Education

University of Mississippi

$26M

Donated $26 million to the construction of a new STEM facility.

Controversies & Challenges

2016

Murder Plot

Thomas Duff was the subject of a murder plot to extort money; 3 individuals were arrested.