Marian Mathison Desrosiers's teaching career spans 25 years at the secondary school level in the fields of American government and history. She received her PhD in humanities from Salve Regina University.

Desrosiers has been a Fulbright scholar, a Taft scholar, a National Endowment for Humanities scholar, and a Gilder Lehrman scholar. In 2006, she received a Schlesinger Library grant to research the World War II WAC director in the Pacific. In 2007, she received a grant from the Rhode Island Council for the Humanities to complete oral history interviews of those who worked with Rhode Island Supreme Court justice Florence Murray.