Miller represents West Virginia's First Congressional District, becoming only the third woman to serve in Congress from the state. Born in Columbus, she has a political family background, with her father, Samuel L. Devine, being a former Ohio congressman. Miller’s political career began in 2004 when she ran for the West Virginia House of Delegates, losing, but successfully returning in 2006 to unseat a Democratic incumbent. She served in the House until 2018, including as House Majority Whip. In 2018, she won the Republican primary for Congress, defeated Richard Ojeda, and was re-elected in 2020. After redistricting in 2022, she was elected to the newly drawn district and re-elected in 2024.