Sean MacDonald is the Vice-President and Co-Director of Pioneer Valley Juniors and has been the coach at Frontier Regional High School since 2003. Coach MacDonald is a member of the American Volleyball Coaches Association (AVCA), Massachusetts Girls Volleyball Coaches Association (MGVCA) and sits on the Board of the Directors for the Volleyball Hall of Fame. He is involved with volleyball as a player, coach, and official. Coach MacDonald was a player on the first boy's team at Mahar Regional HS in Orange, MA, along with the Men's club team at the University of Utah. Sean coaches for the West region of the Baystate Summer Games and previously for Western Mass Junior Olympic Volleyball. He has coached at the college level at DII and was the interim varsity coach for the Agawam boys team. Coach MacDonald is USA Volleyball "Impact", and CAP I Certified.

Sean is a certified PAVO official with a "State" rating. He has held certifications in USA Volleyball along with National Federation of High Schools. His officiating experience includes High school boys and girls matches along with DI, DII, and DIII women's college matches, and DIII men's matches.