Hillsman returned to St. Mary's to be an assistant coach for the men's basketball team. In 1998, he was an associate head coach for the Newport School boys' team before becoming head coach in 1999. He was an assistant coach for both
Siena (1999–2001) and
American University (2001–02), then head coach for
Laurinburg Institute (2002–03) and
The Patterson School (2003–04). He was an assistant coach at
Alabama (2004–05) before arriving at Syracuse in 2005. There, he was also an assistant coach for a year when he was asked to be a head coach by then director of athletics
Daryl Gross. As the Syracuse head coach, Hillsman has led the Orange to eight consecutive postseason appearances, including four straight NCAA berths, 17 postseason victories and eight straight winning seasons, while winning 65 percent of his games. Hillsman was voted the
Big East Conference Coach of the Year in 2008. In the
2015–16 season, his team finished in third place but made it to the
ACC women's tournament finals before losing. They received an at-large bid for the
NCAA women's tournament, where they advanced to the program's first-ever championship game to play Connecticut, losing 82–51. In August 2021, Hillsman resigned from his position as the Syracuse University women's basketball head coach after allegations of misconduct. In September 2021, Hillsman was hired as the head coach by Club Baloncesto Leganés, a professional club in
Madrid, Spain, of the
Liga Endesa. However, due to visa issues and backlash against his hiring, he ultimately did not go to Spain. ==Legal issues==