After scoring 28 points in 34 games, as well as playing in his second World Juniors, during the 1974-75 season, he raised his game to the next level as he put together back-to-back 23 goal 47 point seasons in 1975-76 and 1976-77 while playing first 36 games followed by 33 to average well over a point per game both seasons.
For the 1977-78 season, Leinonen joined MoDo AIK Omskoldvisk in Sweden's Elitserien and did not miss a beat with a 19 goal, 44 point season in 36 games to lead the team in scoring. He also made his senior international debut for Finland at the 1978 World Championships.
Leinonen played one more season with MoDo in 1978-79, winning the league championship. He also competed in the 1979 Worlds before returning to Finland for the 1979-80 season when he joined Karpat Oulu in Finland's SM-liiga. He immediately set career highs in goals and points with 32 goals and 52 points to lead Karpat in scoring. That season he also participated in the 1980 Olympic Games for Finland, where he had a fine showing with 6 goals and 10 points in 7 games to finish second in team scoring by a single point.
He put up an identical 52 points in for Karpat in 1980-81 only this time from 16 goals and a career high 36 assists. He would play in his fourth World Championships in 1981 with 8 points in 8 games.
Later that fall, Leinonen would be a member of the Finnish team for the 1981 Canada Cup tournament. During the tournament, Leinonen signed to play in the NHL with the New York Rangers for the upcoming 1981-82 season. He would play 6 games with the Springfield Indians, scoring 4 goals, but the majority of his season was with New York, seeing action in 53 games, scoring 11 goals and 20 assists as an NHL rookie.
The Rangers qualified for the playoffs that season and drew the Philadelphia Flyers in the opening round. The Flyers won Game 1 easily 4-1 in Manhattan. Game 2, on this date in 1982 was also in New York and it didn't take long for Bobby Clarke to open the scoring for the Flyers just 48 seconds into the contest. The Rangers replied just 1:09 later when Carol Vadnais scored with an assist from Leinonen and Rob McClanahan. The Rangers added a second goal by Ron Dugay to take a 2-1 lead at the 13:47 mark of the first period.
The Rangers added to their lead when Don Maloney scored at 6:17 on a power play from Leinonen and winger Ed Johnstone. Another power play goal by Robbie Ftorek from Johnstone and Leinonen pushed the Rangers lead to 4-1. Ray Allison replied for Philadelphia, but Dave Silk restored the three goal New York lead with 1:10 left in the second period from McClanahan and Leinonen to make it 5-2 after two periods.
McClanahan then scored at 4:31 of the third from Silk and Leinonen. With time winding down, Johnstone scored the seventh Rangers goal at 17:03 on a power play with assists from Leinonen and Silk to give Leinonen a record 6 assists in a single playoff game. Ken Linseman added a goal for the Flyers with just 33 seconds left in the game to make the final score 7-3 for the Rangers.
Leinonen's record still stands to this day, equaled only by Wayne Gretzky five years and a day later in 1987. Oddly, Leinonen would play in 6 other playoff games that season without recording ånother assist!
Leinonen would play a full season with New York in 1982-83, playing in 78 games while scoring 17 goals and coming just one point short of his career high when he totaled 51 points, good for sixth on the Rangers, easily the finest of his time in the NHL.
His 1983-84 season was split between the Rangers, scoring 3 goals and 23 assists for 26 points in 28 games, but he also was with the Tulsa Oilers of the Central Hockey League for 33 games where he average more than a point per game with 15 goals and 38 points. Tulsa would go on to win the Adams Cup as league champions.
He returned to Finland and rejoined Oulu for the following 1984-85 season, once again operating near the point per game average with 34 in 35 games. At the conclusion of the Finnish season, Leinonen briefly returned to the NHL when he played in three regular season games and one playoff game with the Washington Capitals.
When the 1985-86 season began, Leinonen was back again with Karpat for one final season, scoring 23 points in 36 games. He would have one final, abbreviated season in 1986-87 for KalPa Kuopio in Finland, playing in just 8 regular season games and 6 playoff contests before retiring as a player.
His final NHL totals were 162 games, 31 goals and 78 assists for 109 points as well as 20 playoff games, 2 goals and 11 assists, 6 of which came on his record setting night on this day in 1982. Leinonen would also play in two World Juniors, four World Championships, one Olympics and one Canada Cup. In 1995, Leinonen was inducted into the Finnish Hockey Hall of Fame.
Today's featured jersey is a 1981-82 New York Rangers Mikko Leinonen jersey as worn the night he set an NHL record for Most Assists in a Playoff Game. The Rangers had changed to a short lived, modern jersey with their shield crest for two seasons in 1976-77 and 1977-78 before reverting to their classic, diagonally lettered look for the 1978-79 season. This version with the names straight across the back would remain in use through the 1989-90 season until being replaced by vertically arched names for the 1990-91 season.
In today's video segment, highlights of Leinonen's record setting six assist night during the 1982 Stanley Cup playoffs.