In the 2016–17 season, Dahlin scored his first Swedish Hockey League (SHL) goal with Frölunda HC on 12 November 2016 in a game against Karlskrona HK.

He was described as a smart two-way defenceman with a great set of tools, including skating, puck handling, vision, intelligence and shot.

Dan Marr of the NHL Central Scouting Bureau described him as an exceptionally talented prospect that would be able to impact his team's fortune in a way similar to Erik Karlsson and Victor Hedman.

He enjoyed a breakout 2021–22 season, posting new career highs in goals, assists and points and was named to the 2022 NHL All-Star Game.

[17] Dahlin competed in the 2018 World Junior Ice Hockey Championships for Sweden, recording six assists and helping lead the team to win silver.