The versatile back rower was a member of the junior Brumbies growing up before heading north to attend the Southport school on the Gold Coast. After playing for the Queensland schoolboys in 2015, Allen headed back to the nation's capital to play for the ACT U20s for the past two seasons. Allen brings a high work rate to his game and will be one to watch in 2017.
Allen was selected to represent Australia in the Oceania U20s Championships in 2017. He was chosen in the starting lineup for game 2 against Fiji, seeing Australia win 32-24.