She attended Vassar College from 1906 to 1910, and in 1912 she obtained an MA in Latin, with a thesis on the intellectual life of Gaius Asinius Pollio, a Roman consul (40 BC) and historian.

[4]: 87  It is not known exactly when the two women formed a romantic relationship, but when Pierce returned to Vassar to teach art history in 1915 after leaving for graduate work at Columbia University, she and Thallon started living in adjacent rooms in Davison House on campus, and by the late 1910s, they were known to their families and friends as a couple.

[1] She travelled to Greece with Thallon in 1921, a trip which inspired her to enroll in the American School of Classical Studies at Athens (ASCSA).

[3][4]: 92–3  Pierce returned to the United States and spent the spring of 1924 working with Gisela Richter at the Metropolitan Museum of Art.

[8][9] The two also worked together on Hodge Hill's excavations at Lapithos (Cyprus) and Corinth, where they catalogued new finds in collaboration with Elizabeth Van Buren, a specialist in terracottas.

Although she recovered and was able to work in the field again for her final excavation at Pylos in 1958, the stroke affected her mobility and she frequently used a wheelchair.

In 1963, Elizabeth Pierce Blegen deeded the Family's home at 9 Ploutarchou to the American School of Classical Studies in Athens, which also holds her archives, including correspondence, her will, diaries, photographs, and watercolours.

[15] A trust fund left to Vassar College in her will enabled the establishment in 1975 of the Blegen Distinguished Visiting Professorship in Classics.