He moved to Paris' Latin Quarter in 1912 and enlisted in the Foreign Legion in 1914.

Alan Seeger died in the Battle of Somme at Belloy-en-Santerre, France on July 4, 1916.

All of Seeger's work was published posthumously in 1917:

Poems

• An Ode to Natural Beauty
• The Deserted Garden
• The Torture of Cuauhtemoc
• The Nympholept
• The Wanderer
• The Need to Love
• El Extraviado
• La Nue
• All That's Not Love...
• Paris
• The Sultan's Palace
• Fragments
Thirty Sonnets:
• Thirty Sonnets: Sonnet I
• Thirty Sonnets: Sonnet II
• Thirty Sonnets: Sonnet III
• Thirty Sonnets: Sonnet IV
• Thirty Sonnets: Sonnet V
• Thirty Sonnets: Sonnet VI
• Thirty Sonnets: Sonnet VII
• Thirty Sonnets: Sonnet VIII
• Thirty Sonnets: Sonnet IX
• Thirty Sonnets: Sonnet X
• Thirty Sonnets: Sonnet XI
• Thirty Sonnets: Sonnet XII
• Thirty Sonnets: Sonnet XIII
• Thirty Sonnets: Sonnet XIV
• Thirty Sonnets: Sonnet XV
• Thirty Sonnets: Sonnet XVI
• Thirty Sonnets: Kyrenaikos
• Thirty Sonnets: Antinous
• Thirty Sonnets: Vivien
• Thirty Sonnets: I Loved...
• Thirty Sonnets: Virginibus Puerisque...
• Thirty Sonnets: With a Copy of Shakespeare's Sonnets on Leaving College
• Thirty Sonnets: Written in a Volume of the Comtesse de Noailles
• Thirty Sonnets: Coucy
• Thirty Sonnets: Tezcotzinco
• Thirty Sonnets: The Old Lowe House, Staten Island
• Thirty Sonnets: Oneata
• Thirty Sonnets: On the Cliffs, Newport
• Thirty Sonnets: To England at the Outbreak of the Balkan War
• Thirty Sonnets: At the Tomb of Napoleon Before the Elections in America -- November, 1912
• The Rendezvous
• Do You Remember Once...
• The Bayadere
• Eudaemon
• Broceliande
• Lyonesse
• Tithonus
• An Ode to Antares