Léonard and Lagache were both engineers for the Chenard et Walckerautomobile company, and were chosen to drive one of the three entries in the endurance event. Their "Sport" model finished by a four lap margin over another Chenard et Walcker. They drove together the next two years, but failed to finish either time.
Driving for Chenard et Walcker, Léonard won the Coupe Georges Boillot [fr] in 1924. He drove with Lagache to win the second edition of the Spa 24 Hours in 1925, and the pair also finished third in 1926. Léonard won the 1926 Gran Premio de Turismo, a 12-hour race for touring cars held at Circuito Lasarte in Guipúzcoa, Spain.[2]
Following the 1926 season, Chenard et Walcker withdrew from competition. However, in 1932, he was seen driving one of their cars in the Lisieux hillclimb and a one-kilometre race in Strasbourg. The same year, he moved to Saint-Gratien to be near to the company's factory. For the 1937 24 Hours of Le Mans, he managed a private team of Chenard-Walckers owned by Benoît Falchetto [fr] and fielded by Yves Giraud-Cabantous.[3]
