2009-10: Mike Matheson skated for the Lac Saint-Louis Lions midget AAA team in Quebec. In 30 regular season games he scored 5 goals with 6 assists and had 33 penalty minutes. In the playoffs he scored 6 goals with 7 assists and had 10 penalty minutes in 17 games. Lac Saint-Louis reached the Quebec finals before falling to College Antioine-Girouard. Matheson was selected by Shawinigan in the second round (27th overall) of the 2010 QMJHL Entry Draft.
2010-11: Matheson was a team captain for Lac Saint-Louis in his second season as the Lions advanced to the Telus Cup (Canada's midget AAA championship). He led all Lions defensemen with 14 goals and 24 assists and had 72 penalty minutes in 35 games. In the Quebec tournament he scored 7 goals with 18 assists and had 16 penalty minutes in 15 games. The Lions were second in round-robin play and lost to Vancouver North West in the bronze medal game of the Telus Cup. Matheson was named the tournament's top defenseman; finishing with 3 goals and 5 assists in seven games. He committed to playing college hockey at Boston College in 2012-13.
2011-12: Matheson opted for a year of junior hockey – skating for the USHL's defending champion Dubuque Fighting Saints. In an up-and-down season for the Saints, who were riddled by injuries in the first half, Matheson was the leading scorer amongst defensemen with 11 goals and 16 assists in 53 games. He had an even plus/minus for the season and a team-high 84 penalty minutes. In five playoff games he scored 2 of his 4 goals on the power play and had 1 assist and an even plus/minus with 4 penalty minutes. Dubuque was swept by Indiana in a best-of-five second round series. Moncton obtained the QMJHL rights to Matheson in a trade with Shawinigan. He was invited to the NHL Draft Combine and ranked 30th amongst North American skaters in Central Scouting's final rankings prior to the 2012 NHL Draft.
2012-13: Matheson made a smooth transition from the USHL to college hockey in his freshman season at Boston College. The leading scorer amongst Eagles defensemen, he scored 8 goals with 17 assists and was +15 with 78 penalty minutes in 36 games. The defending national champions, Boston College finished second in Hockey East. The Eagles lost to Boston University, 6-3, in the Hockey East semifinals and lost to ECAC Hockey champion Union, 5-1, in an NCAA East Regional semifinal game.
Matheson is quickly becoming a top-flight offensive defenseman. He improved his defensive positioning and awareness last year, but he is still a work in progress in his own zone. He needs to improve his physical play and focus less on the puck as his opponents attack. When he moves out of his zone however, Matheson shines. He has dazzling speed and is a skilled puckhandler who adds tremendous pressure up ice with his skating and his shot.
Matheson will play at least one more season of NCAA hockey at Boston College. However, his package of skills and skating will make it difficult to keep him out of professional hockey for long, and he could well become an NHL defenseman in the next two or three years.