Lagache and Léonard were engineers at automobile manufacturer Chenard et Walcker, and were chosen to drive their "Sport" model in the inaugural 24 Hours of Le Mans. The duo drove a distance of 2,209 km (1,373 mi) over 24 hours and beat another Chenard-Walcker by a four lap margin. Lagache continued to run Le Mans for Chenard et Walcker for the next two years, but was unable to finish the event again.
Lagache also raced a Chenard-Walcker in the inaugural Spa 24 Hours in 1924, finishing second alongside André Pisart. He returned with Léonard to win the event in 1925, and finished third with Léonard in 1926.
He was one of the founders of the tractor manufacturer FAR, and supplied the A to the company name. He was killed in an accident while demonstrating a vehicle in front of army officials in 1938.
