On October 1, 2015, Larsen was appointed to the Michigan Supreme Court by Governor Rick Snyder to replace Justice Mary Beth Kelly, who announced plans to resign and return to private practice, effective October 1, 2015. She was elected on November 8, 2016, to fill the remainder of Kelly's unexpired term, which ran through the end of 2018. Larsen received 58.7% of the vote in a three-way race against Deborah Thomas and Kerry Morgan. She was on Republican presidential nominee Donald Trump's May 2016 list of potential Supreme Court justices. Her service was terminated due to her appointment to the United States Court of Appeals for the Sixth Circuit.
Federal judicial service
On May 8, 2017, President Trump nominated Larsen to serve as a United States Circuit Judge of the United States Court of Appeals for the Sixth Circuit, to the seat soon to be vacated by Judge David McKeague. Larsen's nomination was held up for months by Michigan's Democratic U.S. Senators, Debbie Stabenow and Gary Peters. The pair initially refused to return their blue slips for Larsen, an informal United States Senate practice that essentially gives Senators veto power over federal judicial nominees from their home state. Larsen met separately with Peters and Stabenow on July 26, 2017. Stabenow and Peters both returned blue slips in August 2017, allowing Larsen's hearing to move forward. A hearing on Larsen's nomination before the Senate Judiciary Committee was held on September 6, 2017. On October 5, 2017, the Judiciary Committee voted on a party-line vote of 11–9 to recommend her to the full U.S. Senate for a confirmation vote. Senate Majority LeaderMitch McConnell filed a cloturemotion to limit debate on Larsen's nomination on October 26, 2017, clearing the path for the full Senate to vote on Larsen's nomination in the first week of November 2017. The Senate voted to invoke cloture and thus end debate on Larsen's nomination on October 31, 2017, by a vote of 60–38, with Stabenow and Peters voting to proceed with the nomination and give Larsen a final up-or-down vote before the full Senate. On November 1, 2017, Larsen was confirmed by the full Senate by the same 60–38 vote. Both Stabenow and Peters, along with six other Senate Democrats, joined all 52 Senate Republicans voting to confirm Larsen. She received her commission on November 2, 2017.