Salvat joined the French Army in May 1938. By July 1939, he was a sergeant under General Eugène Mittelhauser, stationed in Tripoli, Libya. Salvat refused to accept the armistice of 22 June 1940 and joined the Free France forces in Mandatory Palestine under Captain Raphaël Folliot. Stationed in Moascar, Egypt, he fought in the Battle of Sidi Barrani, Sollum, Bardia, the Siege of Tobruk, Benghazi and El Agueila under Lieutenant Roger Barberot. He fought in the First Battle of El Alamein in Egypt in July 1942 under General Marie-Pierre Kœnig and the Second Battle of El Alamein in October–November 1942. He became a lieutenant in December 1943 and fought in the Italian campaign. He subsequently received the Colonial Medal for his service in Libya.