He grew up in Ronan, Montana, and he is a member of the Confederated Salish and Kootenai Tribes of the Flathead Nation.

[1] He served as a Democratic member of the Montana House of Representatives for District 95 from 2017 until 2021.

[1][2] In 2020, Morigeau won the Democratic party nomination for state auditor, but was defeated in the general election by Republican Troy Downing.

[3] Less than a week after the 2020 general election, incumbent state senator Nate McConnell resigned.

Subsequently, Morigeau was formally appointed by the Missoula County Board of Commissioners to serve in the Montana Senate.