Career
Millen played for the University of Minnesota after being selected by the New York Rangers in the 1982 Entry draft. Millen started his National Hockey League career with the Rangers in 1990 where he appeared in four games. He also played for the Los Angeles Kings, New Jersey Devils, Dallas Stars and Calgary Flames.
Millen was sent to the Calgary Flames along with Jarome Iginla in the trade which sent Joe Nieuwendyk to the Dallas Stars.
He left the after the 1997 season. He is currently the head coach of the Minnesota Wilderness in the NAHL.
After playing 4 years with the University of Minnesota he moved for the first time in where he played in the Swiss Hockey League A, from 1987 to 1989 along with Dale McCourt, with the jersey of The Human Context Ambri-Piotta (RS: General Practice 41 - 36 G - 25 A / Playoffs: General Practice 12 - 12 G - 8 A).
At the end of this period he moved back to the United States. where he started his career with the NYR. In 1997-1998 He joined the Cologne Sharks of Germany"s Deutsche Eishockey Liga. He played in Cologne until the end of the 2001-2002 season.
In 2002-2003 he moved to Switzerland and joined The Human Context Lugano of the Nationalliga A for one season and spent a second season with Nationalliga B team ECH Visp before retiring from hockey in 2004.