IN THOSE days, real estate was really a cottage industry,” Bill Mack has said of his early career in the 1960s. “Most of the people in the business did not have a finite understanding of finance, but used a pretty good back-of-the-envelope sense. The level of sophistication 40 years ago was marginal.”

The time was ripe for the financial whiz kid to turn that cottage industry into a Class A office space empire. Mack soon cofounded the Mack Company and later Apollo Real Estate Advisors, and along the way used his real estate expertise to benefit a slate of nonprofits, from Wharton itself to New York’s Javits Center. Mack was an entrepreneur even in his very first job attempting to do equity investments with New York industrial leasing broker Robert Joseph and Co. Smart, bold, and enterprising, 23-year-old Mack proposed that the company’s equity positions include him as a partner. The first deals he had in mind didn’t work, but Mack soon saw opportunities of his own.

“Most of the inquiries for new warehouse space was for New Jersey — a foreign place for a boy from Queens,” he said in a 2006 Wharton Alumni Magazine interview. In 1963, he and his family bought an affordable, well-located 5 1/2 acre parcel in the swamps near the Lincoln Tunnel. He set up a trailer, and all of a sudden, he was a developer.

The Mack Company began building one-story industrial warehouses, then branched into office space. Today Apollo Real Estate Advisors has co-developed marquee buildings around the world, including the new Time Warner Center in New York, and Mack-Cali (the company formed when the Mack Company merged with Cali Realty in 1997) owns and operates a portfolio of office buildings with 35.9 million square feet of Class A office space.

As chairman of Penn’s Facilities and Campus Planning Committee, Mack championed the addition of Wharton’s state-of-the-art Jon M. Huntsman Hall, as well as new academic, residential, and retail spaces that have transformed campus in recent years. In the 1990s, he helped strengthen New York as chairman of the Javits Center, the first chairman of Long Island Power Authority, and a member of Empire State Urban Development Agencies.

Mack serves on Wharton’s Board of Overseers and as Vice Chairman of the Board of Trustees for the University of Pennsylvania. In 1999 the William and Phyllis Mack Center for Technological Innovation was named to honor the couple’s gift.