At the
2018 National Draft, Walsh was drafted number 1 by the Carlton Football Club. This was not seen as a surprise to many, who had expected him to be a lock for the first pick. Walsh was given the number 18 and impressed many during pre-season. Sam made his debut in Round 1 of the
2019 AFL season against at the
MCG, where he finished with 24 disposals. He kicked his first goal against in round 3. Walsh earned an AFL Rising Star nomination in Round 4, following Carlton's two point loss to , after collecting 28 possessions (13 contested), seven clearances, six tackles and a goal. He also earned a contract extension with the Blues, keeping him at the club until 2022. Sam was awarded with the 2019 AFL rising star. After a promising season in 2020, which culminated in his finishing second in the Carlton Best and Fairest, Walsh exploded in season 2021, garnering his maiden All Australian selection, his first John Nicholls Medal as the Carlton Football Club Best and Fairest, and finishing fourth in the Brownlow Medal. In 2020, despite having only had a short career at that point, he was named in the
St Joseph’s College team of champions, recognising the best
VFL/AFL players to have attended the school. In February 2022, Walsh signed a 4 year extension to stay with the Blues until at least the end of 2026. In February 2026, Walsh signed an eight-year contract extension with Carlton to the end of 2034. The deal was the longest and most lucrative in Carlton's history, estimated to be worth over $10 million. ==Statistics==