2009-10: A successful 59 game tour of the BCHL greeted the small center, tallying 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.
MacMillan is a skilled two-way forward with good speed and vision along with good playmaking skills. The lanky forward needs to add more muscle mass and size to his thin frame in order to play his physical style. He has a few more years of development at the NCAA level to prepare his overall game for the professional level.
MacMillan will be returning for his sophomore year at the UND where the talent centerman will be expected to bring more offense and continue his development as a two-way player. He will help the Fighting Sioux challenge for a NCAA National Championship for the upcoming season.