NCAA While at
Yale University, Lyon was named Ivy League co-Rookie of the Year in 2014. After leading the nation in save percentage, shutouts and goals-against average, Lyon was presented with the
Ken Dryden Award (given to the best goalie in the ECAC) his sophomore season, while receiving First-Team AHCA/CCM All-America, First-Team All-ECAC, First-Team All-New England as well as First-Team All-Ivy League honors. He was also the winner of the J. Murray Murdoch Award as Yale's Most Valuable Player. Individual awards kept rolling in for Lyon after the 2015–16 season, as he repeated as
Ken Dryden Award recipient and also landed spots on the All-ECAC First Team, the All-Ivy League First Team and the All-New England First Team for the second straight year.
Professional Philadelphia Flyers Lyon opted to forgo his senior season at Yale and signed an entry-level contract with the
Philadelphia Flyers of the
National Hockey League (NHL) on April 5, 2016. in 2020 Lyon made his first NHL start February 1, 2018 in a 4–3 loss to the
New Jersey Devils. On February 18, 2018, Lyon recorded his first NHL win with the Flyers after replacing an injured
Michal Neuvirth in the second period. Lyon saved 25 of 26 shots by the
New York Rangers en route to a 7–4 victory. On May 9, 2018, in a playoff win over the
Charlotte Checkers, Lyon saved 94 of 95 shots faced in a record-setting 146 minutes 48 seconds, making it the longest game in AHL history. The game went to the fifth overtime, with the Phantoms winning 2–1. On November 5, 2018, Lyon was recalled to Philadelphia following an injury to Michal Neuvirth. Lyon was again recalled to the Flyers on November 16. On January 15, 2020, the Flyers recalled Lyon to the NHL following an injury to
Carter Hart. On February 1, 2020, Lyon recorded his first NHL win since March 22, 2018.
Carolina Hurricanes goaltenders Following the
2020–21 season, his fifth within the Philadelphia Flyers organization, Lyon left as a free agent and was signed to a one-year, two-way contract with the
Carolina Hurricanes on July 30, 2021. Lyon played the majority of the season with the Hurricanes' AHL affiliate
Chicago Wolves, only tallying two games with the Hurricanes. With the Wolves, Lyon finished the regular season with 18 wins and 3 shutouts, earning him the
Hap Holmes Memorial Award for the AHL goaltender with the lowest goals against average. He tallied two additional shutouts in the playoffs, including a 28-save shutout in the final game to win the
Calder Cup.
Florida Panthers On July 13, 2022, Lyon signed a two-way free agent contract with the Florida Panthers. Lyon posting a 7–2 record with a 2.00 GAA over his last nine starts for the
Charlotte Checkers. With Panthers starting goaltender
Sergei Bobrovsky ill and regular backup goaltender
Spencer Knight participating in the NHL's player assistance program for undisclosed issues, Lyon was called up to the NHL. He proceeded to lead the team on a lengthy winning streak that brought the team back into contention for the
2023 Stanley Cup playoffs, earning the nickname "
the Lyon King." Such was his success that he retained the starting role even after Bobrovsky returned, with the latter praising him, saying he "basically saved our season." Lyon started the opening games of the Panthers' first round playoff series against the
Boston Bruins. However, with the Bruins leading the Panthers two games to one following Game 3, coach
Paul Maurice opted to return Bobrovsky to the net, stating that he felt Lyon was fatigued. Bobrovsky proceeded to lead the team to victory against the Bruins, and onward through the second and third rounds of the playoffs to the
2023 Stanley Cup Final against the
Vegas Golden Knights. Lyon served as backup goaltender. He took the ice against in Game 2 of the Finals, relieving Bobrovsky after he allowed four goals.
Detroit Red Wings On July 1, 2023, Lyon signed a two-year, $1.8 million contract with the
Detroit Red Wings. On November 27, 2024, Lyon sustained a lower-body injury, was placed on injured reserve. During the
2024–25 season, he posted a 14–9–1 record with a 2.81 GAA and .896 save percentage in 30 games.
Buffalo Sabres On July 1, 2025, Lyon, a free agent, was signed to a two-year, $3 million contract with the
Buffalo Sabres. Following a January 29, 2026, win against the
Los Angeles Kings, Lyon set the Sabres records for consecutive wins, at 10, breaking
Gerry Desjardins' record set in 1976. ==International play==