Riordan played three seasons for the Friars, averaging 11.2 points and 8.2 rebounds per game over his college career.

Riordan played 9 seasons (1968–1977) in the National Basketball Association as a member of the New York Knicks and Baltimore/Capital/Washington Bullets.

He was traded along with Dave Stallworth and an undisclosed amount of cash to the Baltimore Bullets for Earl Monroe on November 11, 1971.

Riordan served in the United States Air Force, where he was a mechanic and played basketball at night.

[3][4][5] Source[6] This biographical article relating to a United States basketball player, coach, or other figure born in the 1940s is a stub.