[6] On 2 November 2010, Larsson fought Timrå IK forward Daniel Corso, receiving a cut eyebrow during the altercation.

[8] Larsson's play in the 2010–11 season earned him a nomination for the Elitserien Rookie of the Year award, which Mattias Ekholm would eventually win.

[10] Seen as a move towards rebuilding the Devils defence corps, Larsson was rated by the NHL Central Scouting Bureau as the top European-based prospect available in the draft.

[16] Upon making his NHL debut, Larsson averaged 24 minutes per game alongside defencemen Andy Greene and Henrik Tallinder.

[17] Shortly after his 19th birthday, Larsson scored his first career NHL goal in the first period of an eventual 3–1 loss to the Washington Capitals on 11 November.

[20] Despite missing two games in late December to attend his grandmother's funeral, Larsson led all rookie defencemen with two goals and 11 assists for 13 points.

[21] Due to his play during the first three months of the season, Larsson was selected to the NHL All-Star Rookie SuperSkills Competition on 12 January 2012, along with teammate Adam Henrique.

[29] Despite his success during the regular season, Larsson struggled to enter the Devils' lineup in the 2012 Stanley Cup playoffs as he failed to make an appearance during their opening-round matchup against the Florida Panthers.

[30] He eventually made his postseason debut in Game 2 of the Eastern Conference semifinals against the Philadelphia Flyers after Ilya Kovalchuk suffered an injury.

[35] Larsson tallied four goals and 15 assists in 33 games with Albany before making his season debut on 31 January 2013 in place of Mark Fayne.

The Devils made him a qualifying offer to retain his NHL rights and on 5 July 2015, he filed for salary arbitration under the CBA.

[49][50] Oilers President and General Manager Peter Chiarelli defended the trade, saying: "(Larsson) is a younger player, not by much, by a year.

"[51] Prior to the start of the 2016–17 season, Chiarelli also added Milan Lucic, Patrick Maroon, and Zack Kassian to the Oilers lineup.

[54] In this new role, they helped the Oilers start the season with a 7–2–1 record and a .750 points percentage that ranks second to the Montreal Canadiens through their first ten games.

[55] Although Larsson only tallied three points while averaging 20:19 of ice time through 16 games, coach Todd McLellan praised him for being a "stabilizing factor" on the blue line.

As a member of the Oilers' top defensive pairing, Larsson had tallied two goals and four assists through 36 games and was tied for eighth in the NHL in hits with 106.

[57] Through the second half of the season, Larsson and Klefbom continued to hold a strong presence as the Oilers' top defensive pairing.

[68] Larsson began the season strong, tallying three goals and one assist through his first 25 games, before being placed on Injured Reserve due to an upper-body injury on 1 December.

As a result of his personal struggles during the 2017–18 season, Larsson was the Oilers nominee for the Bill Masterton Memorial Trophy as a player who most exemplifies "perseverance, sportsmanship and dedication to hockey.

[75] He subsequently missed two exhibition games with back tightness but returned to the ice for the Oilers' season opener in Gothenburg, Sweden.

[76] As well, the Oilers losing record of 10-10–1 to begin the season resulted in head coach Todd McLellan being replaced with Ken Hitchcock.

[84] After blocking a shot during the Oiler's 2019–20 season opener against the Vancouver Canucks, Larsson was placed on long-term injured reserve with a fractured right fibula.

"[89] Prior to the start of the 2021–22 NHL season, Larsson, Jordan Eberle, Yanni Gourde, and Jaden Schwartz were named the four alternative captains for the Kraken.

Larsson's play in high-risk situations subsequently earned him praise from Kraken coach Dave Hakstol, who described him as a measured professional who is a warrior for the team.

[91] He continued to be an asset for the Kraken on the penalty kill as he led the team with 52 minutes of ice time while shorthanded by early December.

[96] Once Giordano and Lauzon were dealt at the NHL trade deadline, Larsson and Vince Dunn became consistent defensive partners for the remainder of the season.

[98] Prior to the start of the 2022–23 NHL season, Larsson was again named one of four alternate captains for the Kraken alongside Eberle, Gourde, and Schwartz.

[100] By December, Larsson had accumulated two goals and five assists while playing with Dunn as they helped the Kraken have 53.7% of unblocked shot attempts during games.

[97] The following month, Larsson tied Eberle for the longest points streak in franchise history by scoring a goal and six assists through seven consecutive games.

[1] The following year, he played alongside Tim Erixon and David Rundblad on Team Sweden at the 2010 World Junior Championships where he earned a bronze medal.