She was appointed by Governor Paul Cellucci and served as an associate justice of the Massachusetts Supreme Judicial Court from 2000 until her death.
Following this, Sosman was chief of the Civil Division at the U.S. Attorney's Office for the District of Massachusetts in Boston, serving from 1986 to 1989.
Governor Paul Cellucci nominated Sosman to the Massachusetts Supreme Judicial Court on September 6, 2000 at the age of 49.
[1] Sosman was one of three justices to dissent in the Goodridge v. Department of Public Health case, which legalized same-sex marriage in Massachusetts.
[citation needed] On July 20, 2004, Sosman was outed as a closeted lesbian by Fox News personality Bill O'Reilly.