Robertson made his debut in Round 1 of the 2020 AFL season against Hawthorn at the MCG. He played 15 games in 2021 and earned a two-year contract extension. He made eight appearances in 2022 including all three of Brisbane’s finals. He played 18 games in 2023, including a grand final appearance in Brisbane's loss against Collingwood, in which he scored a goal. Robertson again extended his contract at the conclusion of the 2023 season, penning a two-year extension to the end of the 2025 season, ending speculation that he would seek a trade to a Western Australian club.
He was subject to widespread fanfare following an incident where his shirt was ripped in a match against Collingwood at Marvel Stadium in Round 23 of the 2023 season. Robertson continued to play with the ripped shirt until he took it off completely following a tackle from Beau McCreery.[2] His ripped shirt was ultimately auctioned off for the Royal Children’s Hospital charity ahead of the 2023 finals.[3]
^The 2020 season was played with 17 home-and-away matches per team (down from 22) and 16-minute quarters with time on (down from 20-minute quarters with time on) due to the impact of the COVID-19 pandemic.