Clarence Willis Eastman was born in Concord, New Hampshire on January 3, 1873. He received a Bachelor's degree from Worchester Polytechnic Institute in 1894. He studied German Literature at the Universities of Gottingen and Leipzig from 1895 to 1898, and received the degrees of Master of Arts and Doctor of Philosophy from the University if Leipzig in 1898. From 1898 until 1907, he taught German at the University of Iowa, and, during the summers, taught at the University of Chicago and the University of Missouri.

Eastman's publications include Die Syntax des Dativs bei Notker (dissertation, 1898); Wilhelm Hauff's "Lichtenstein"(1901); An Account of Some of the Ancestors of Harry Thompson and Myra Hull (1916); Goethe's Poems (editor, 1941).

Eastman became Associate Professor of German Language and Literature at Amherst College in 1907, and full Professor in 1909. He remained at Amherst until his retirement in 1943. He died March 12, 1952.