After the war Valentin again served as a parachute instructor and directed his attention toward his lifelong ambition. While still in the French Army he developed the jumping technique known as the "Valentin position", allowing him better control of his movements in the air. In February 1948 he set a record for the longest free fall without a respirator (15,600 feet). He subsequently made another free fall of 20,200 feet, and set a record for the longest night free fall (14,550 feet). Shortly thereafter he left the army after ten years of service to continue his experiments as a civilian.