[10] In 2014, he announced his run for state Senate in the 31st district seat, challenging first-term incumbent Mike Green in the Republican primary election.
[11] Daley ran for the Senate seat again in 2018 and won, defeating state Representative Gary Glenn in the August 2018 Republican primary, 58–41%.
[15] In January 2021, Daley was one of 10 Michigan Senate Republicans who signed a letter to Congress in support of President Donald Trump's attempt to overturn his loss in the 2020 presidential election and remain in power.
[18] In November 2023, Daley joined the Senate Republican leadership team for the 102nd Michigan Legislature, as minority caucus chair.
[19] In April 2023, Daley voted against a bill to amend an antiquated Michigan law that made it a misdemeanor for an unmarried man and woman to cohabitate or to "lewdly and lasciviously" associate.
[21][22] Daley is a member of the Michigan Workforce Development Board; in 2024, Governor Gretchen Whitmer appointed him to a second term, expiring January 1, 2027.