Mellon is the chairman of Pan AM Systems Inc., an industrial services company based in New Hampshire. He is the grandson of the late Andrew W. Mellon, who was the United States Secretary of the Treasury from 1921 to 1932. The Mellon family’s fortune totals approximately $11.5 billion, per an estimate by Forbes. Timothy Mellon has stayed out of the public spotlight to the point that, the New York Times reported, Republican operatives had to search his name online before accepting his contribution ahead of the midterm elections in 2018. Mellon reportedly spends most of his time on his ranch in Wyoming. Timothy and Patricia Mellon were named No.10 on a list of top 12 political mega donors, according to a report by Issue One, a nonpartisan center for Responsive Politics, which tracks money in federal elections. The couple contributed $70 million mostly to Republican candidates and Super PACs between January 2009 and December 2020. *Called social safety net programs "Slavery Redux" *In August 2021, Mellon donated $53.1 million in stock to the State of Texas to pay for construction of walls along the US–Mexico border. *In August 2023, it was revealed that Mellon donated $5 million via a Super PAC to the presidential campaign of Democratic candidate Robert F. Kennedy Jr. *Top donor to Trump Super PAC