Robert Silliman Hillyer was born in East Orange, New Jersey. A graduate of Harvard University, he was editor of the Harvard Advocate and part of the group known as the Harvard Aesthetes. During World War I, he served as an ambulance driver alongside his classmate John Dos Passos. After the war, Hillyer taught English at Harvard. He received the Pulitzer Prize for poetry in 1934 for his Collected Verse and was named Boylston Professor of Rhetoric and Oratory in 1937. After leaving Harvard in 1945, he taught at Kenyon College and the University of Delaware.

Hillyer’s collections of poetry include Eight Harvard Poets (1917), which included work by E.E. Cummings and John Dos Passos; Sonnets and Other Lyrics (1917); The Five Books of Youth (1920); Alchemy: A Symphonic Poem (1920); The Halt in the Garden (1925); A Letter to Robert Frost and Others (1937); In a Time of Mistrust (1939); Pattern of a Day (1940); My Heart for Hostage (1942); The Death of Captain Nemo (1949); The Suburb by the Sea: New Poems (1952); and Collected Poems (1961).

Hillyer was a proponent of traditional forms in his own work and the work of others. He wrote many sonnets and, in A Letter to Robert Frost and Others, compiled a collection of seven verse letters in rhymed couplets. The letters were addressed to Frost, whom he admired; friends and professors; his son; and Queen Nefertiti. He was critical of Modernist poets and particularly opposed Ezra Pound’s Bollingen Prize in light of Pound’s past support of fascism.