Tommy is a member of the following organizations:
- Town Meeting (at large)
- Town Meeting Recorded Vote Coalition
- Town Meeting Green Caucus
- Committee to Commemorate John Wilson
- Democratic Town Committee (elected)
- Brookline PAX (board member)
- Progressive Democrats of Massachusetts (sustaining member)
- Friends of Hall’s Pond (board member 2014-2019)
- Friends of the Carlton Street Footbridge (board member 2008-2019)
- Benevolent and Protective Order of Elks, Lodge #886, Brookline