She served as president of the Women's Trade Union of Minneapolis and was a member of the Minnesota Farmer Labor Party.

Born in Minneapolis, Minnesota, to Irish immigrant parents, Cain went to public schools in the city and to St. Anthony's Convent.

[2] After the Nineteenth Amendment was ratified and upheld in the 1922 Supreme Court case of Leser v Garnett, Cain and three other women won seats in the Minnesota House of Representatives in the 1922 election.

During Cain's single session in office (1923-1924), she co-sponsored a bill about anti-masking, which prevented Ku Klux Klan members from wearing masks or hoods in public (House File No.

In 1923, Cain advocated for passage of an Equal Rights Amendment to the Minnesota Constitution, but the effort ultimately failed.