 After beginning his career at club level with Glen Rovers, Clifford joined the Cork minor team as a 15-year-old in 1950, captaining the team to the All-Ireland Minor Championship in 1951.He was almost immediately promoted to the Cork senior team and won his first All-Ireland Championship as non-playing substitute in 1953 before claiming a second winners' medal on the field of the play in 1954 after scoring the winning goal in the final.A severe head injury ended Clifford's inter-county career in 1956, by which time he had also won two Munster Championship medals.