per his Wikipedia page...
After retiring in 1998, McMillan stayed with the Seattle franchise, earning a place as an assistant coach. He held this role until 2000, when he was named interim coach of the Sonics. Although the team missed the playoffs during his first year as coach, he provided a major turnaround after the franchise got off to a miserable start that year, and he was hired as head coach for the next 2001-02 campaign. McMillan led the clubs to the playoffs in his second year before back-to-back mediocre seasons. In his final year as Sonics coach, McMillan led the team to a Northwest Division title in 2005.
After 19 years with the Seattle organization, McMillan left Seattle on July 7, 2005 to become the head coach of the Portland Trail Blazers. He took over a team riddled with cap problems and off-the-court drama, but steadily calmed the waters in Portland.
McMillan was an assistant coach under Mike Krzyzewski for the US national team in the 2006 FIBA World Championship and in the 2008 Beijing Olympics, winning bronze and gold medals, respectively. He is also a member of the National Junior College Basketball Hall of Fame, due to his All-American performance at Chowan.
On December 5, 2009, McMillan ruptured his right Achilles tendon while scrimmaging with the Trail Blazers during practice. McMillian coached much of the season in a protective boot after surgery and led the team to 50 wins in spite of a historic number of injuries to his key players.
On March 15, 2012, McMillan was fired as the head coach of the Portland Trail Blazers.