Debuting for the Australian national rugby team in 2021 in the series against France, he was brought to fame by a turnover in the late stages of the game, securing Australia's victory.

Born in the north Queensland town of Babinda, Swain grew up in nearby Cairns until he was 15,[2] when he was scouted by Brisbane Boys' College and offered a scholarship to finish his schooling there.

During his final year of school,[2] the Tuggeranong Vikings along with the Brumbies offered Swain a move to Canberra to play for the Brumbies U20s team, and ultimately the National Rugby Championship team Canberra Vikings.

[4] He continued to play mostly off the bench in 2018 and 2019 before starting 13 games at lock in the 2020 Super Rugby AU.

[5] In July 2020 Swain made his Wallabies debut, coming off the bench against France and earned another 9 caps that year against New Zealand, South Africa, Japan and Argentina.