Dineen played junior hockey for the St. Michaels College Majors and the Neil McNeil Maroons and won the Memorial Cup in 1961 with the Majors. In 1963 he joined the Canadian National Team and played in the 1964 and 1968 Olympics. As well he represented Canada in the 1965, 1966, and 1967 World Championships. He turned pro in 1968 in the Minnesota North Stars' organization and played four games for the NHL team in 1968-69. Dineen, a native of Montreal, made West Springfield, Massachusetts his home with his wife and daughter for well over 30 years.