Larry Cain took up canoeing at the age of 11 and was further motivated in the sport by watching John Wood’s performance at the 1976 Summer Olympics. He joined the national team in 1979 and, two years later, became the junior world champion in the C1-500 and C1-1000. He moved up to the senior division in 1982, barely missing the podium in both events with fourth-place finishes. His fortunes greatly improved at the 1984 Summer Olympics, however, where he won the C1-500 and was runner-up, behind Ulli Eicke of West Germany, in the C1-1000.
Although he continued to compete for many years, the 1984 Summer Olympics were the pinnacle of Cain’s athletic career. His only other major international podium finish came at the 1989 World Championships, where he was second in the C1-1000 behind Ivans Klementjevs of the Soviet Union. He also came close to the podium at the 1988 Summer Olympics, where he finished fourth in the C1-1000, and the 1993 World Championships, where he had the same placement in the C2-1000 with David Frost. Frost and Cain would go on to compete at the 1992 Summer Olympics, where they placed seventh and ninth in the C2-1000 and C1-500 respectively. Cain retired from active competition in 1996 and took up teaching, coaching, and motivational speaking. In addition to being named a Member of the Order of Canada in 1984, he was inducted into Canada’s Sports Hall of Fame in 1997.