Now in his sixth NHL season, Lehkonen has totaled 149 points (74g/75a) in 396 career NHL contests, all with Montreal, who selected him in the second round (55th overall) of the 2013 NHL Draft. He has collected 12 points (6g/6a) in 33 playoff contests, including a career-best three goals in 17 Stanley Cup Playoff games last season to help Montreal reach the Stanley Cup Final for the first time since 1993. Lehkonen scored the overtime game-winning goal in Game 6 of Montreal's semifinals series against Vegas to clinch the Canadiens a spot in the Stanley Cup Final.
Prior to coming to North America, the 5-foot-11, 179-pound left wing played two seasons in the Swedish Hockey League from 2014-16, totaling 49 points (24g/25a) in 96 contests for Frolunda and added 25 points (14g/11a) in a combined 29 playoff games. He paced the league in playoff points (19) and goals (11) in 2016 to help Frolunda capture the SHL championship. Lehkonen's 19 points surpassed Daniel Alfredsson to set a Frolunda team record for playoff points in a season.
The Piikkio, Finland, native also played three seasons in Finland's top professional league (Liiga) from 2011-14, collecting 54 points (23g/31a) in 96 contests for KalPa and TPS.
Internationally, Lehkonen helped Finland capture gold at the 2014 IIHF World Junior Championship, serving as an alternate captain and recording four points (2g/2a) in six games. He also represented his country at the 2013 IIHF Under-18 World Championship, leading the team in assists (6) and points (9) to help Finland win bronze.