Maurice Lefèbvre spent a lifetime dedicated to aquatic pursuits, joining EN Tourcoing at a young age. As an active competitor, he was selected to represent France internationally 87 times, 69 of which were in the role of team captain. His most notable appearances came at the 1936 and 1948 Summer Olympics, where the French squad placed fourth and sixth respectively. Following the end of his competitive days, he served as a swimming coach in Mouscron as well as being the director of the city pool in Maubeuge. After his retirement, he returned to his native Tourcoing.