Mills defeated incumbent Karen Ray in the 2008 primary, and served for 2 terms in the NC House from 2009 until 2013.

In 2012, Mills sought the Republican nomination for Lieutenant Governor, but he lost to eventual winner Dan Forest.

[3] Following then incumbent Republican John Fraley's decision not to seek re-election to the state house in 2020, Mills sought election to his old seat and won.

[4] Mills ran unsuccessfully for North Carolina's 10th congressional district in 2024, losing the Republican primary to eventual winner Pat Harrigan.

In May 2021, Mills voted for North Carolina House bill 453 which prohibited abortion based on race, sex, or suspected disability.