O'Neill was son of Nobel Prize-winning playwright Eugene O'Neill and the elder O'Neill's first wife, Kathleen Jenkins. The couple divorced in 1912. O'Neill once said he did not even meet his father until age 12. O'Neill graduated Phi Beta Kappa from Yale University in 1932, where he was a member of Skull and Bones secret student society. He earned a PhD in philosophy in 1936.