In 2006, Millan began a 2-year stint with the minor junior hockeySpruce Grove Saints in the Alberta Junior Hockey League. Upon committing to his collegiate freshman year at Boston University, Millan backstopped the Terriers to the 2009 NCAA Championship title and was selected as the Hockey EastRookie of the Year, Hockey East Second All-Star Team, and the Tournament MVP. By the conclusion of his four-year collegiate career, Millan finished as the Boston Terriers' all-time leader in victories, games played, and saves. He was also selected as BU's most valuable player in two consecutive years. After his 2008–2009 championship season, Millan was selected by the Colorado Avalanche in the fifth round of the 2009 NHL Entry Draft. On May 11, 2012, Millan embarked on his professional career by signing to a two-year entry level contract with the Avalanche. After initially attending training camp with the Avs' AHL affiliate Lake Erie Monsters, Millan was reassigned to make his pro debut with the Denver Cutthroats of the CHL, a secondary affiliate of the Avalanche. On October 20, 2012, Millan made his first start as a professional only to be pulled after yielding 6 goals in a defeat to the Missouri Mavericks. Millan quickly rebounded to settle in net with the Cutthroats and on November 13, 2012, he recorded his first and the Cutthroats first franchise shut-out, in a 6–0 win over the Arizona Sundogs. Millan continued his form to be named as the CHL's First Star of the Month for November. On December 29, 2012, Millan was recalled to the Monsters and made his AHL debut in a 4–0 defeat against the Charlotte Checkers on January 4, 2013. He was then returned to the Cutthroats and was twice awarded CHL goaltender of the week to finish with an even record before an opening round defeat to the Allen Americans in the playoffs. At the conclusion of his entry-level contract, Millan was not retained by the Avalanche and was released as a free agent. With limited playing opportunities, Millan opted to retire from professional hockey to take up a job in Calgary. His record in 55 professional games was 22–21–6.
