[1] She represents the electoral district of Memramcook-Tantramar as a member of the Green Party, of which she is one of the deputy leaders.

Mitton ran as the Green Party candidate in the 2014 election, finishing third behind Bernard LeBlanc and incumbent Mike Olscamp.

Mitton is a member of the Standing Committees on Public Accounts, Climate Change and Environmental Stewardship, Private Bills, and Social Policy.

She is also the Green Caucus Advocate on matters of Healthy and Inclusive Communities, Climate Justice, and Education.

[2] On September 14, 2023, Mitton as well as Kevin Arseneau were both appointed as Deputy Leaders of the Green Party of New Brunswick.