NBA player for the Detroit Pistons and Boston Celtics who became a coach in the 1990s, leading the Celtics, Milwaukee Bucks and Los Angeles Clippers.
He attended Villanova University, majoring in business and leading the basketball team to a championship game against UCLA.
He scored the NBA's first three-pointer in a 1979 game.
He had four children with his wife Kathy.
He coached the Boston Celtics with future Hall of Famers Larry Bird and Kevin McHale, and together they won the 1981 NBA Championship.