After being injured in high school, Lefebvre starred with the Edmonton Wildcats for 3 seasons before joining the Edmonton Eskimos in 1966. Playing 16 games and catching 9 passes for an impressive 25.3 yards average and 3 touchdowns, he won the Dr. Beattie Martin Trophy as best rookie in the Western Conference. After 2 more season in Edmonton, Lefebvre was disappointed to learn he was traded to the last place Montreal Alouettes. His unfortunately short 1970 season was redeemed by a Grey Cup victory, in which he caught the final touchdown. Returning to the Eskimos, he was the Dick Suderman Trophy winner for best Canadian in a Grey Cup loss to the Ottawa Rough Riders in 1973. His best season was 1974, when he caught 36 passes for 575 yards and played in the Grey Cup, losing to Montreal. In 1975 he won his second Grey Cup ring, again against Montreal.
While mostly a receiver, Lefebvre was also a first string punter, punting 83 times in 1968, 102 times in 1973, 103 times in 1974, and 127 times in his final season. He could also play defensive back, intercepting 7 passes and returning 2 for touchdowns (both in 1967.) Finally, he attempted 2 passes during his career, completing both.
He is married to Sandi and they have 4 children: Cheri, Brad, Julie and Jesse.
He is a long standing founding member of Athletes in Action, joining them in 1972.
Lefebvre built and directed Canada's first Circle Square youth ranch in Halkirk, Alberta, where he and his family served for eight years. After founding and pastoring a small church in Kelowna, BC in 1988, Garry returned to Edmonton in 1992 as director of the 100 Huntley Street counselling center. In 1995, he brought the ministry of Athletes International Ministries to Canada, where he is presently Executive Director. In January 2009, he became the Regional Co-ordinator of Edmonton and area for Promise Keepers Canada.