[11] Australia's performance at the Asian Championship saw them qualify for the 2018 FIBA Under-17 Basketball World Cup, where Rantall was picked for the roster.
During the 2019 season, he played 12 games in the NAB League with GWV Rebels, kicking 11 goals and averaging 25 disposals and seven tackles.
[18][19] After his season at GWV Rebels, Rantall represented Vic Country at the 2019 AFL Under 18 Championships, playing in all four games and averaging 18.8 disposals and 3.5 tackles.
[23] During the 2019 AFL Draft Combine, Rantall showcased his endurance and broke the record for the 2 km time trial.
[27] In April 2021, After collecting 28 disposals in a Victorian Football League (VFL) game with Collingwood's reserves side, Rantall made his senior debut against Essendon in the annual Anzac Day match, which was the sixth round of the 2021 AFL season.