2016 When incumbent Republican Representative
Ruth Petroff announced her retirement, Gierau announced his candidacy for the seat. Gierau ran unopposed for the Democratic nomination and was unopposed for the general election.
2018 When incumbent Republican state senator
Leland Christensen ran for
state treasurer and did not seek reelection in the State Senate, Gierau ran to fill his seat. Gierau was unopposed in the Democratic primary, and defeated Republican Kate Mead in the general election. ==References==