Mills enters his first season with the Ducks, second in the Atlantic League, and tenth in professional baseball. He was acquired by the Flock via a trade with the Southern Maryland Blue Crabs on June 6, 2023. In 2022 with Southern Maryland, the southpaw went 9-1 with a 2.99 ERA across 12 game starts, firing 72.1 innings, surrendering 63 hits, 27 runs (24 earned), and 23 walks, while striking out 56. He also pitched for Quintana Roo (Mexico) during the 2022 campaign, going 0-1 with a 9.00 ERA in four game starts.

Mills was originally selected by the Washington Nationals in the 18^th round of the 2014 MLB June Amateur Draft from Sprayberry High School in Marietta, Georgia. He spent four seasons in the Nationals organization, (2014-2017), two in the Philadelphia Phillies organization (2017-18), and two in the Miam Marlins organization (2018-2019). Mills also pitched for Team Great Britain in the 2023 World Baseball Classic.