D on Ahern is a self-made American billionaire and the owner of Ahern Rentals, one of the largest privately owned equipment rental companies in the United States. He took over his family's small Las Vegas rental business in the 1970s and transformed it from a local operation into a national powerhouse with a vast fleet of construction and industrial equipment.

In addition to his core rental business, Ahern also owns Xtreme Manufacturing, a company that builds heavy-duty, high-capacity telehandlers and other construction machinery, creating a vertically integrated business model. His career has been marked by resilience; he successfully navigated a Chapter 11 bankruptcy during the financial crisis and has since brought the company back to a position of strength. Ahern is also known for his political activities, as a major donor to the Republican Party and a prominent supporter of Donald Trump. In 2022, he sold his equipment rental business to United Rentals for $2 billion.