Fontan-associated protein-losing enteropathy is difficult to treat and associated with poor prognosis. Cardiac rehabilitation and exercise are thought to have beneficial effects for patients with Fontan circulation. We report the case of a young adult patient palliated to Fontan circulation, with a decade-long history of symptoms related to protein-losing enteropathy. At age 23 years, he appreciated an improvement in symptoms and laboratory values after cardiac rehabilitation and prescriptive exercise.