Following law school, Baldacci returned to Bangor and started a law practice. He was first elected to the Bangor City Council in 1996 and re-elected in 1999, also serving a term as City Council chairman and Mayor — in Bangor, these two titles belong to one position — and remaining on the council until 2002. Baldacci was elected to the City Council again in 2011 in a race that also unseated two incumbents, and was re-elected in 2014. In July 2015, Baldacci announced that he would run for the Democratic nomination for
Maine's 2nd congressional district, challenging incumbent Republican
Bruce Poliquin. He dropped out in February 2016 and endorsed fellow Democrat
Emily Cain for the nomination. Baldacci was again elected City Council chairman and mayor of Bangor in November 2016. In a 2021 interview, Baldacci recalls deciding during his final term as City Councilor that he would run for the Maine Senate. He explained that his experiences navigating and becoming familiar with local policies over his 12 years on the council had helped him feel prepared for the position, and that his daughters were in college by then, making the increased time commitment more feasible for his family. In
2020, Baldacci ran for the Maine Senate District 9 seat vacated by term-limited incumbent
Geoffrey Gratwick. In the Democratic primary, he defeated
Victoria Kornfield 53%–47%, and in the November general election he received 55% of the vote in the three-way race with Republican Sean Hinkley and independent Kristie Miner. Since his 2020 term began, Baldacci has served on the Health and Human Services committee and is the chair of State and Local Government committee. Baldacci was reelected in
2022, with 59% of the vote, and again in
2024 with 58% of the vote. On January 12, 2026, Baldacci announced his candidacy for Maine's 2nd congressional district after incumbent Democrat
Jared Golden announced his decision not to run for a fifth term. ==Personal life==