He was born in New York City on October 14, 1864, the only child of Mortimer Lent Earle and Mercy Josephine Allen.

At the latter in 1887 he was placed in charge of the excavations of the site of ancient Sikyon by Professor Augustus C. Merriam of Columbia.

From 1895 to 1898 he served as associate professor in Greek and Latin at Bryn Mawr College, before returning to Barnard in 1898 just as it was about to become part of Columbia University.

In 1890 he was appointed a member of the American Philological Association and served as vice-president from 1902 until his untimely death in 1905.

His numerous contributions to learned periodicals were collected in The Classical Papers of Mortimer Lamson Earle, with a Memoir (New York, 1912).