Hedman ushered in a new era for the Tampa Bay Lightning when he was named the 11th captain in team history Sept. 18, 2024. He replaced longtime captain Steven Stamkos when the forward signed with the Nashville Predators as a free agent.

Hedman was Sweden's captain for the 4 Nations Face-Off, the first time he captained his country in international play since he joined the NHL as the No. 2 pick in the 2009 NHL Draft. He was an alternate for Sweden at the 2024 IIHF World Championship, where it won bronze. Hedman was then named one of the first six players to Team Sweden's preliminary roster for the Olympic Winter Games Milano Cortina and he became the fifth player and first defenseman in Lightning history with 800 points in a 4-3 win against the Anaheim Ducks at Benchmark International Arena on Oct. 25, 2025.

Hedman is the first Lightning defenseman to play 1,000 games in the NHL; he was plus-1 in 23:55 of ice time in a 4-0 win against the Dallas Stars at Amalie Arena on Dec. 4, 2023. He was the third player in team history to reach the milestone, joining Vincent Lecavalier (1,037) and Stamkos (1,027).

The two-time Stanley Cup champion (2020, 2021), was voted Conn Smythe Trophy winner as most valuable player of the 2020 Stanley Cup Playoffs, five-time Norris Trophy finalist and voted as best defenseman in the NHL in 2018. The 6-foot-6 defenseman from Sweden, has been everything the Lightning could have asked for when they drafted him. His 10 goals in the 2020 playoffs were the most by a defenseman since Brian Leetch of the New York Rangers scored 11 in 1994, and he averaged 26:20 of ice time, the most of any player who got as far as the second round of the playoffs.

After earning Rookie of the Year honors in the Swedish Elite League as an 18-year-old, Hedman joined the Lightning for the 2009-10 season and had an assist in his first NHL game, a 6-3 loss to the Atlanta Thrashers on Oct. 3. On Dec. 5, 2009, Hedman scored his first NHL goal in a 4-0 victory against the New York Islanders.

He honed his defensive game early and has since become a standout at both ends of the ice with his blend of size (6-foot-6, 229 pounds) and speed.

Hedman's play during the 2015 playoffs helped Tampa Bay advance to the Stanley Cup Final, a six-game loss to the Chicago Blackhawks.

He was named an NHL Second-Team All-Star in 2017, then won the Norris Trophy in 2018 after helping the Lightning win the Atlantic Division and finish first in the Eastern Conference. Despite missing 12 games with injury in 2018-19, Hedman was again named an NHL Second-Team All-Star. He was selected to play in the NHL All-Star Game for the second time in 2020 and was again named a Second-Team All-Star.

Hedman hails from Ornskoldsvik, Sweden, which has produced NHL stars Markus Naslund, Peter Forsberg, Henrik Sedin and Daniel Sedin. Many high-level players have spent time with Modo, the local club team where Hedman's father, Olle, served as an equipment manager. Hedman joined the senior-league team at 16 and in two seasons playing in the men's league scored nine goals and 25 points in 82 games.