Andre Agassi is not a morning person, at least not this day. As the former tennis star walks into a private meeting room at Manhattan’s Pierre hotel for an 8:30 a.m. photo shoot, he chides his partner, money manager Bobby Turner, for scheduling an early East Coast start. Agassi had arrived from his Las Vegas home the day before, went with Turner to Flushing Meadows in Queens to watch Roger Federer beat Richard Gasquet for a spot in the U.S. Open quarterfinals, then dined in Midtown before finishing the evening at the new Central Park South apartment of hedge fund manager Bill Ackman.

Yet Agassi shakes off the jet lag and gamely steps up to be photographed. “I’m not going to get any better looking as the day goes on,” he says. Then he sits down over breakfast to discuss his real passion: charter school education. He and Turner have teamed up to create a joint venture, the Turner-Agassi Charter School Facilities Fund, to support the sector. The firm just closed its second fund, expecting to raise $400 million in equity capital from investors including the University Endowment Fund of the University of Michigan and private wealth clients of Bank of America Merrill Lynch. Over the next five years, the fund, managed by Turner’s social investing outfit Turner Impact Capital, will invest some $1 billion to develop as many as 130 charter schools across the U.S. The venture’s first fund, launched in 2011, has to date built 50 schools educating a total of about 22,800 students.

Agassi, 45, earned much of his education on the courts. He began his professional tennis career in 1986, at the age of 16, and went on to win all four of the sport’s major titles. He started his own foundation in 2001, then devoted himself fully to philanthropy after retiring from the game in 2006, with a particular interest in at-risk youth and charter schools. He has raised $175 million over 15 years for charter schools, beginning with the Andre Agassi College Preparatory Academy, which opened in Las Vegas in 2001; its 2009 class had 100 percent graduation and college acceptance rates.

Agassi wrote about his charter school success in his 2009 autobiography, Open. When Turner, then a partner and head of the real estate business at Los Angeles–based money manager Canyon Partners, read the book, he had to get in touch.