Léonard and Lagache were both engineers for the Chenard et Walcker automobile company, and were chosen to drive one of the three entries in the endurance event.

Driving for Chenard et Walcker, Léonard won the Coupe Georges Boillot [fr] in 1924.

Léonard won the 1926 Gran Premio de Turismo, a 12-hour race for touring cars held at Circuito Lasarte in Guipúzcoa, Spain.

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.

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