[6] In 2004, after Maine's post-census legislative redistricting, Jackson ran for re-election in the new House District 1 as a Democrat.

[8] In 2008, Jackson ran and won Maine State Senate District 35, defeating Republican Daniel DeVeau 11,188–6,593.

[9] He would be re-elected in 2010, holding the seat amidst a Republican wave that saw the GOP claim its first government trifecta in Maine since 1963.

On July 10, 2013, Jackson was elected Majority Leader of the Maine Senate after the resignation of fellow Democrat Seth Goodall.

Senator from Vermont Bernie Sanders' campaign and cast his superdelegate vote for him at the 2016 Democratic National Convention.

[23] After the primaries, Jackson threw his support behind Vice President Joe Biden and Senator Kamala Harris.

In 2010, Jackson wrote a bill which would have "prohibited the Maine Department of Conservation from employing foreign laborers at state-owned logging sites".

[27] Jackson attended Allagash Consolidated Community High School before obtaining an A.A. in business from the University of Maine at Fort Kent.