As a teenager he was mentored by H. P. Lovecraft, who had been alerted to the boy's brilliance by his teacher Maurice W. Moe and his participation in amateur journalism.
Lovecraft quickly came to think of Galpin as an honorary "grandson", and nicknamed him "Alfredus"; the two wrote a number of poems for each other and engaged in the Gallomo correspondence circle together.
Galpin most notably introduced to Lovecraft the ideas of Friedrich Nietzsche, and the fiction of Clark Ashton Smith.
He taught at Wisconsin for many decades, publishing papers such as "Italian Echoes in Albert Camus" and several books including De Sanctis On Dante and a volume of the correspondence of Fauriel.
The University of Wisconsin has an annual Alfred and Isabella Panzini Galpin Italian Scholarship award which is named in his honour.