He played junior for the Windsor Spitfires and the Hamilton Tiger Cubs, both Detroit Red Wings' farm teams. Riggin turned pro with the Edmonton Flyers for 8 games in 1955-56 and then for a full season in 1956-57, winning the top rookie award. He spent most of his pro career with the Flyers, with two 9 game callups to the Red Wings in 1959-60 and 1962-63. He retired in 1963. Dennis is the father of NHL goaltender Pat.