D onald Bren is an American billionaire real estate magnate and the sole chairman and owner of the Irvine Company, a major private real estate development firm. He is America's richest property developer, with a vast and highly valuable portfolio of properties concentrated in Southern California. The son of a real estate investor, Bren started his own homebuilding company before joining a consortium to purchase the historic Irvine Ranch from its founding family in 1977.

Over the next two decades, Bren systematically bought out his partners to become the sole owner of the 93,000-acre ranch, which covers a huge portion of Orange County. As the master planner of this massive landholding, he has overseen the development of a number of master-planned communities, including the city of Irvine itself, as well as a massive portfolio of office buildings, shopping centers, and apartment complexes. He is known for his long-term hold strategy and his meticulous attention to design and planning. He is also a major philanthropist, having donated vast tracts of land for permanent conservation.