At the 1980 Summer Paralympics in Arnhem, Netherlands, he competed in both track and swimming, winning gold medals in the men's 100-metre sprint, javelin and 100-meter backstroke, a silver medal in the 100-metre breaststroke, and a bronze medal in the 100-metre freestyle.
Lapalme competed on the men's wheelchair basketball team at both the 1988 Summer Paralympics in Seoul, South Korea and the 1992 Summer Paralympics in Barcelona, Spain. but the team did not medal at either event.
Although no longer active as a Paralympic competitor after 1992, he remained involved in sports as late as the early 2010s as captain of the Ottawa Sledgehammers, the city's sledge hockey team. Lapalme died on November 1, 2021 in Hull, Quebec at the age of 62.
Following the end of his Paralympic career he was cast in his first acting role, as Jerome of Sandy Cove in Phil Comeau's 1994 film Jerome's Secret. He subsequently had small parts in the films Bleeders and Two Lovers and a Bear, and an episode of the television series F/X: The Series.
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- "Bronze for Canada". Edmonton Journal, August 12, 1990.
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- "Denis Orval Lapalme". The Ottawa Citizen. November 3, 2021. Retrieved November 24, 2021.
- "The Acadian Tale About A Mysterious Amputee". Canada AM, March 30, 1995.