John P. Reardon is an American administrator who was the athletic director at Harvard from 1978 to 1990 and executive director of the Harvard Alumni Association from 1990 to 2014.

Reardon graduated from Harvard College in 1960. He was student manager of the Harvard Crimson football team during the 1959 season. He earned his Master of Business Administration from the Wharton School of the University of Pennsylvania.^[1] In 1963, Reardon joined the Boston Redevelopment Authority as an administrative assistant for operations.^[2]

In 1965, Reardon accepted a position in the Harvard admissions office. He rose to the position of associate dean of admissions and financial aid for Harvard and Radcliffe Colleges. On September 12, 1977, he was named Harvard's athletic director. He took office the following February.^[3] Reardon took over the department during a $30 million athletic construction project that included the construction of the Gordon Track and Tennis Center, renovations to Harvard Stadium, the Bright-Landry Hockey Center, and Dillon Fieldhouse, and the conversion of the Briggs Athletic Center into a basketball arena.^[1][4] He also oversaw the expanding the women's programs.^[5] During his tenure, the 1988–89 Harvard Crimson men's ice hockey team won the NCAA Division I championship and the Harvard crew won the 1985 Grand Challenge Cup at the Henley Royal Regatta.^[5]

In 1988, Reardon took on the additional role of associate vice president for university relations. On May 8, 1989, he announced that he would step down as AD to become the executive director of the Harvard Alumni Association.^[6] He remained AD until his successor, Bill Cleary, took over in 1990. He remained head of the Harvard Alumni Association until his retirement in 2014.^[5]