It's not often that a player passes on his first real opportunity to play in the NHL, but Klingberg did just that. It might have been the best move he ever made.

Feeling he needed more seasoning to compete consistently at the NHL level, Klingberg remained in his native Sweden for the 2013-14 season. He responded with 28 points (11 goals, 17 assists) and a plus-8 rating in 50 games with Frolunda of the Swedish Hockey League.

Klingberg then went to North America for the 2014-15 season and had a big impact. The native of Gothenburg, Sweden, who was selected by the Dallas Stars in the fifth round (No. 131) of the 2010 NHL Draft, made his NHL debut Nov. 11, 2014. He scored his first NHL goal nine days later. Both games were against the Arizona Coyotes. Klingberg led Stars defensemen, and NHL rookies at the position, with 40 points (11 goals, 29 assists) in 65 games in 2014-15. He finished fifth in the Calder Trophy voting for NHL rookie of the year and signed a seven-year contract April 17, 2015.

A steady point producer, Klingberg played in his first NHL All-Star Game in 2018. He scored the series-winning goal in overtime against the Nashville Predators in Game 6 of the 2019 Western Conference First Round and scored 21 points (four goals, 17 assists) in 26 games during the Stars' run to the Stanley Cup Final in 2020.

Klingberg signed a one-year contract with the Anaheim Ducks on July 29, 2022. He left the Stars first in team history among defensemen in game-winning goals (21), tied for third with Derian Hatcher in goals (71), and third in assists (303) and points (374). He led the Stars at the position in scoring in seven of his eight NHL seasons and is the only defenseman in Dallas/Minnesota North Stars history with at least 30 points in each of his first eight seasons.

Klingberg had 24 points (eight goals, 16 assists) in 50 games before he was traded to the Minnesota Wild on March 3, 2023, for Andrej Sustr, Nikita Nesterenko and a fourth-round pick in the 2025 NHL Draft. He signed a one-year, $4.15 million contract with the Toronto Maple Leafs on July 1, 2023.

Klingberg signed a one-year contract with the Edmonton Oilers on Jan. 17, 2025, after recovering from hip surgery that ended his season in December 2023. He signed a one-year, $4 million contract with the San Jose Sharks on July 1, 2025.