Boylan began his coaching career as a
player-coach in Switzerland from 1982 to 1986 and led
Vevey Basket to its first championship in its 30-year history. At age 31, he moved back to the States becoming an assistant under
Jud Heathcote at
Michigan State University from 1986 to 1989. Boylan then took over head coaching duties at the
University of New Hampshire, succeeding
Gerry Friel. UNH fired Boylan after three dismal seasons in the spring of 1992. In 1992 Boylan entered the
NBA as a video coordinator and advance scout for the
Cleveland Cavaliers. In 1997, he moved over to the
Vancouver Grizzlies, serving as an assistant under
Brian Hill and later
Lionel Hollins. In 2001, Boylan became a member of
Frank Johnson's coaching staff in
Phoenix, and remained working for the
Phoenix Suns under Johnson's successor
Scott Skiles. After Skiles was fired in 2002, Boylan worked with
Terry Stotts for the
Atlanta Hawks during the
2003–04 NBA season. In 2004, Boylan became lead assistant to Skiles, who had taken over as head coach of the
Chicago Bulls. On December 27, 2007, after the firing of Scott Skiles, Jim was named the interim coach for the Bulls for the remaining season. Boylan was not retained at the conclusion of the season after compiling a 24–32 record with the Bulls. On May 14, 2008, he was hired as an assistant to Scott Skiles by the
Milwaukee Bucks. When Skiles resigned in January 2013, Boylan became head coach of the Bucks. The team went 22–28 under his guidance and made the playoffs, but were swept in the first round by the
Miami Heat. At the end of the season, the Bucks decided not to give Boylan a new contract. Instead, Boylan would be hired by the
Cleveland Cavaliers later on in the same year. He would later on be a part of the
2015–16 Cleveland Cavaliers squad to earn an NBA Finals championship over the 73–9
Golden State Warriors. ==Head coaching record==