A graduate of Florida State University, Giardino joined the Ottawa Rough Riders in 1967. Rushing 3 times for 15 yards and blocking a kick in his rookie season was good enough to win the Gruen Trophy as best rookie in the East (this at a time when only Canadians were eligible for the award.) He later became a starting linebacker and dependable back up fullback, his best year being 1971 when he rushed for 201 yards. On defense he intercepted six passes, returning three for touchdowns, and took fumble recoveries back for another three touchdowns, including 146 yards in 1972, still the second best in CFL history On offense he rushed for 536 yards and caught 44 passes during his career. He was a Grey Cup champion three times: 1968, 1969 and 1973. Finally, he was the head coach of the Ottawa Sooners junior team in 1994, leading them to a 7 win and 2 loss season.