Thilthorpe debuted in round 6 of the 2021 AFL season, as he was impressive with 16 disposals and kicked 5 goals.[2] His 5 goals is the highest ever by a Crows debutant, tied with Josh Rachele who matched the record a year later. Jason Dunstall noted the performance as "the emergence of a future star."[3]
In round 13, against St Kilda, Thilthorpe kicked the match winning goal over his head on his opposite boot in the last minute of the game. It completed Adelaide's 36-point comeback.[4] Thilthorpe was rewarded with the NAB AFL Rising Star nomination for Round 13.[5]
After a strong off-season prior to 2024, Thilthorpe sustained a knee injury in a pre-season match against West Coast. He had surgery and missed more than four months of football.[6] Thilthorpe finally made his return in July of 2024, coming on as the substitute in the fourth quarter against St Kilda and kicking two match-winning goals.[7] He played his 50th game just a few weeks later against Geelong, and kicked three goals in the same game, the first of which was his 50th career goal.[8] Following a successful return from injury in the latter half of the season, Thilthorpe signed a contract extension until the end of 2028.[9]
