An Academy graduate who claimed the AFL Rising Star in his first season, 2016, Mills joined the Sydney Swans' leadership group at just 21 and was appointed captain in 2024. The 188cm New South Welshman collected the Bob Skilton Medal and All-Australian selection in 2022, and fought back from injury to feature 11 times in 2025. He has played 197 AFL games and kicked 30 goals.