2009-10: Mark MacMillan had a successful 59 game tour of the BCHL. The small center scored 26 goals and 54 assists with the Alberni Valley Bulldogs.
2010-11: MacMillan concluded his junior career playing for the Penticton Vees (BCHL). He was limited to 40 games, missing time with a broken wrist, and scored 21 goals with 36 assists and amassed 43 PMs. In three playoff games, he had 5 assists with 6 PMs. MacMillan represented Canada West in the World Junior A U-19 Challenge and scored 2 goals with 2 PMs in five games.
2011-12: MacMillan had an excellent freshman season for UND where he played mostly on the top-two lines, scoring seven goals along with 17 assists in 42 NCAA games. The playmaking centerman had a seven-game point streak snapped in the NCAA West Region championship game where the Fighting Sioux lost 5-2 to the University of Minnesota ending their season. He improved his two-way game while gaining valuable experience from all the injuries on the team this season and winning the WCHA Championship against University of Denver.
2012-13: MacMillan skated in all 42 games for North Dakota as a sophomore — the only Fighting Sioux forward to do so. Skating at times with older brother Mitch MacMillan, who transferred from St. Cloud State, he scored 13 goals with 12 assists and was +10 with 28 penalty minutes. North Dakota finished third in the WCHA and received an at-large bid to the NCAA West Regional after an overtime loss to Colorado College in the WCHA quarterfinals. The Fighting Sioux defeated Niagara before falling to eventual national champion Yale in the West Regional final.
2013-14: MacMillan was the third-leading scorer for the University of North Dakota as a junior behind sophomore Rocco Grimaldi (Florida) and Flyers’ prospect Michael Parks. He scored 10 goals with 16 assists and was -4 with 26 penalty minutes. North Dakota finished second in the newly-formed National Collegiate Hockey Conference and lost to Miami, 3-0, in the NCHA semifinals; earning an at-large bid to the NCAA Midwest Regional after defeating Western Michigan in the league’s third-place game. The Fighting Sioux defeated Wisconsin and Ferris State to win the regional; falling to Minnesota 2-1 in the Frozen Four semifinal on a goal in the game’s final second.
2014-15: MacMillan was leading North Dakota with 16 goals in 29 games when he suffered a broken knee cap while blocking a shot in a February game against St. Cloud State; subsequently undergoing season-ending surgery. He finished the year with 9 assists and was +9 with 27 penalty minutes. The Fighting Sioux finished first in the National Collegiate Hockey Conference regular season, falling 3-1 to St. Cloud State in the NCHC semifinals and 5-1 to Denver in the third-place game. North Dakota received an at-large bid to the NCAA tournament, defeating Quinnipiac and St. Cloud State by identical 4-1 scores to capture the NCAA West Regional. The Sioux lost to Boston University, 5-3, in the Frozen Four semifinals. MacMillan signed a two-year entry-level contract with Montreal in April 2015.
2015-16: MacMillan skated in 62 games for Montreal AHL affiliate St. John’s in his first pro season after beginning the year with the ECHL’s Brampton Beast. He scored 6 goals with 11 assists and was -10 with 41 penalty minutes for the IceCaps. St. John’s missed the AHL playoffs, finishing fifth in the North Division. MacMillan scored 2 goals with 3 assists and was -2 with 2 penalty minutes in six games with Brampton.
MacMillan's skating is his biggest strength, as he is quick on his feet, can change speeds at the drop of a dime and has solid edge work, making him a strong, defensive-minded forward. Not overly offensive-minded, he did manage his highest goal total with the University of North Dakota in 2014-15, tapping into some goal-scoring potential. He is still on the lanky side of the physical spectrum, but he plays the body well and is solid in his own end. At this stage in his development, MacMillan's ceiling is likely that of a bottom-six player who can be relied upon to kill penalties and play well down low. His transition to the center position and 57-percent win-rate on face-offs in his last year with the Fighting Sioux demonstrated his versatility.
MacMillan skated for Montreal AHL affiliate St. John's in 2015-16, playing a shutdown, bottom-six role with the IceCaps. One of the top defensive forwards in college hockey during his time at North Dakota, that is expected to be his role at the pro level. He is still fairly low on the depth chart with the Canadiens and will need an impressive training camp in 2016 to crack the NHL lineup.