Chapman was drafted by Fremantle with their first pick, the fourteenth overall, in the
2020 AFL draft. He made his AFL debut in the second round of the
2021 AFL season in Fremantle's win over
Greater Western Sydney. Round one of the
2022 AFL season versus saw Chapman receive much praise for his 'game-winning Intercept play' in which he spoiled an opponent's kick on the goal line conceding no score with just seven seconds left in the match. With just a point the difference had the ball been rushed through for a behind the game would have been a draw. Chapman received a
2022 AFL Rising Star nomination for his performance in round 8 against North Melbourne at
Optus Stadium, collecting 25 disposals, 12 intercept possession and five marks. Chapman finished the home-and-away season having played fifteen games, and featured in both of Fremantle's finals appearances. Chapman played in Fremantle's first three game of the
2023 AFL season, but an injury sustained during the first
Western Derby saw him ruled out for the rest of the year. Heath returned to the Fremantle line-up in round seven of the
2024 AFL season against the . ==Statistics==