Charles began his coaching as a young player in England, but he had no idea then the success coaching would bring to him. Charles remained with Reynolds High School for three years before the University of Portland hired Charles as its men's soccer coach in 1986. In 1989, the university expanded his duties to include both the men's and women's teams. He would continue coaching the UP teams until his death. In his last season (2002), the UP women's team won the National Collegiate Athletic Association (NCAA) championship. During his tenure as the men's coach, Charles had a hand in beginning the career of numerous outstanding future players, including American men's internationals Kasey Keller and Steve Cherundolo, American women's internationals Tiffeny Milbrett and Shannon MacMillan and Canadian international Christine Sinclair. Other players include Yari Allnutt, Scott Benedetti, Conor Casey, Kelly Gray, Nate Jaqua and Wade Webber.