Answer:
Harvard has the most presidential alumni (eight presidents): John Adams, John Quincy Adams, Rutherford Hayes, Theodore Roosevelt, Franklin Roosevelt , John Kennedy, George W. Bush, and Barack Obama. Hayes and Obama went there only for law school and Bush went for his MBA. The other 5 went for undergrad degrees.
Yale is second with 5 (Taft, Ford (law school), G.H.W. Bush, Clinton (law school), and G. W. Bush)