He enrolled at Yale University where he was a member of the secret society Skull and Bones[1]: 155 and was among the "Renaissance" generation of talented Yale-educated writers (which includes alumni such as Stephen Vincent Benét, Henry R. Luce, Archibald MacLeish, Cole Porter, and Thornton Wilder).
Following graduation Putnam traveled to Europe and worked a series of odd jobs including a brief period as an assistant editor for the Atlantic Monthly Press and writing advertising copy for an insurance company.
Matthiessen acknowledges in his essay “To the Memory of Phelps Putnam” “he sketched a poem too vast ever to be able to shoulder the weight of writing it”.
[2] Putnam wrote little in his later years, which largely consists of poetry published in various magazines and lyrics for a musical collaboration with Harl McDonald entitled Songs of Conquest: Cycle for Chorus of Mixed Voices (1937).
Twice married (to Ruth Peters and Una Fayerweather) Putnam had numerous affairs, including trysts with Katharine Hepburn and painter Russell Cheney.