After law school, she became a consumer protection attorney for the Federal Trade Commission in Washington, D.C. She went into private practice in Portland and represented small businesses.

[3] In 2006, incumbent Democratic State Representative Brad Avakian decided to retire to run for the Oregon Senate.

[4] On April 30, 2008, commissioners from Washington and Multnomah Counties appointed Bonamici to represent Oregon's 17th Senate district.

[8] After Wu resigned from Congress, Bonamici announced her candidacy for the special election to replace him,[9] touting endorsements from former Governor Barbara Roberts, former Congresswoman Elizabeth Furse, and incumbent Oregon Attorney General John Kroger, among others.

[12] Before her election to Congress, Bonamici resigned from the Oregon Senate on November 21,[13] and was replaced by Elizabeth Steiner Hayward in December.

"[18] In January 2023, Bonamici was one of 13 cosponsors of an amendment to the Constitution of the United States extending the right to vote to citizens sixteen years of age or older.

[19] During the 117th Congress, Bonamici voted with President Joe Biden's stated position 99.1% of the time according to a FiveThirtyEight analysis.