Mills won the 2016 NAB AFL Rising Star Award for his outstanding breakout season.

Mills later revealed the Swans' academy was the major influence in his decision to play Australian rules football instead of rugby union when he was a teenager.

[6] He won the under 16's best and fairest at fourteen years of age for the Mosman Swans and he was ultimately named club champion in 2012.

Following a promising debut season, Mills re-signed with the Swans on a five-year contract that will see him remain at the club until the end of 2023.

[12] At the start of 2022 he was named one of Sydney's co-captains,[13] and later that year signed a contract extension with the Swans to keep him at the club until the end of 2029.