Näslund was selected in the second round as the 37th overall pick in the 1979 NHL Entry Draft, by the Montreal Canadiens. After playing for three more years in Sweden, he joined the Canadiens for the 1982–83 NHL season. He was the first European-born player to play for the Canadiens. In his rookie season of 1982–83, Näslund scored 71 points in 74 games, becoming the Canadiens' third leading scorer behind Guy Lafleur and Ryan Walter, who had 76 and 75 points respectively. That year, he was recognized as the left winger on the NHL All-Rookie Team. His offensive abilities quickly endeared him to Montreal fans, and he was given the nickname of "Le Petit Viking", a reference to his Nordic heritage and his short stature. Teammate Mario Tremblay jokingly said when Näslund arrived that the Habs only received half of a player and the other half would arrive later. Näslund had his best NHL season in. He scored 43 goals and 67 assists, the first Montreal player to top 100 points since Lafleur had 125 in, and the last Canadien to reach 100 points or finish among the league's top ten scorers as of. His 67 assists were an NHL record for a left winger until Kevin Stevens of the Pittsburgh Penguins scored 69 in. In the 1986 Stanley Cup playoffs, the speedy Näslund was Montreal's top point-getter, as the Canadiens won their twenty-third Stanley Cup, their first since 1979. He also led the Montreal Canadiens in scoring in, albeit with 30 points fewer than he had the preceding season. During his NHL career, Näslund was an infrequent visitor to the penalty box. Never logging more than 19 penalty minutes in any season during his career, his gentlemanly play was recognized when he was voted the winner of the Lady Byng Memorial Trophy, beating Wayne Gretzky in the voting. During the 1988 NHL All-Star Game, his five assists established a record, and he was instrumental in helping Mario Lemieux set the All-Star Game record with six points. After a sub-par season, worn down by the relatively long NHL seasons, Näslund left the Canadiens to return to Europe. He played one year in Switzerland, followed by three seasons in his native Sweden. He returned to the NHL to play for the Boston Bruins in the lockout shortened season, and retired from hockey thereafter. Näslund ranks twelfth on the Canadiens all-time scoring list, with 612 points in 617 regular season games. Despite both playing hockey, he is not related to Markus Näslund.
Näslund is one of Swedish hockey's all-time great players, and as such represented his country at numerous international tournaments. As a junior, he represented Sweden at the 1978 and 1979 World Junior Hockey Championship, winning a silver medal in 1978 and a bronze medal the following year. Näslund would go on to participate in five World Hockey Championships, winning a bronze in 1979, a silver in 1981 and a gold in 1991, his last appearance at the event. Because the World Championships occur at the same time as the Stanley Cup playoffs, Näslund was often not available for the event during his best years in Montreal. His sole appearance as an active NHL player came in 1983. Näslund did get the chance to play for Sweden against the NHL's best players at the 1984, 1987 and 1991 Canada Cup, the forerunner to the World Cup. The Swedes lost to Canada in the finals of the 1984 event. They reached the semifinal game in both 1987 and 1991, losing to the USSR and Canada respectively. Näslund also participated in two Winter Olympics, in 1980 and 1994. Sweden won the bronze medal in 1980 and the gold medal in 1994, that year defeating Canada in a memorable shootout. The gold medal in 1994 gave Näslund the distinction of having won the Stanley Cup, World Championship and Olympic Championship in his career, and becoming the first member of the Triple Gold Club. As general manager for the Swedish national men's ice hockey team, Näslund helped construct the gold medal-winning team at the 2006 Winter Olympics.
