Delestraint was captured in the beginning of the First World War and spent it as a prisoner of war. After the end of the war he remained in the army and supported the use of armored forces. He also befriended Charles de Gaulle.
Delestraint retired 1939 but was recalled for service after the outbreak of World War II. In June 3_4 1940, he led the counterattack of armored troops against Germans in Abbeville.
After the surrender of France he retired to Bourg-en-Bresse where Henri Frenay recruited him for French Resistance. He began to organize resistance in Lyon. He clandestinely visited Charles de Gaulle in London and agreed to lead the Armée Secrète group. He returned to France in March 24 1943. However, due to informant Rene Hardy, he was arrested by the Gestapo in June 9 and interrogated by Klaus Barbie. He was taken to Struhof and then to Dachau where he was executed in April 19 1945.