He played junior hockey for the St. Catharines TeePees from 1953-55, winning the Memorial Cup in 1954. He turned pro in 1955-56 with the Winnipeg Warriors of the WHL and won the rookie of the year award as the team won the Edinburgh Cup. Cullen played alongside brother Brian, and his younger brother Raymond followed in their footsteps, going to play in the NHL as well. After 1959-60, Cullen played four seasons with the Buffalo Bisons of the American Hockey League and won the Calder Cup in 1963. He retired in 1964.