Sérot enlisted in the infantry in 1915, then saw action in the Battle of Argonne and received the Croix de Guerre. The following year he was an officer candidate at Saint-Cyr. In 1917 he transferred to aviation, flying reconnaissance missions.
In 1919, Lieutenant Sérot transferred to the intelligence service. In 1923 he was sent to Strasbourg. In 1933, he became deputy chief of station Belfort, or Military Communications Service (MCS).
He married Berthe Grünfelder (1898–1971).
During the " Phoney War " period (1939–1940), Sérot was sent behind German lines with a series of false identity papers to perform reconnaissance missions. After the 1940 defeat, he helped organize the counter-espionage section of the Service de Renseignements de l'Armée de l'Air ("Air Forces Intelligence Service") newly created by Colonel George Ronin, classmate of General Jean Bergeret. After the Allied landings in North Africa in November 1942, he and Paul Paillole went there to organize the new Service de Sécurité Militaire ("Military Intelligence Service").
In June 23, 1943 his wife was arrested by the Gestapo in Clermont-Ferrand and was deported to Ravensbruck in Germany. In 1945, she was rescued and released by Count Folke Bernadotte. This led to a friendship between the two men.
In 1944, Captain Sérot headed the SSM.
Sérot, now a Colonel in the Armee de l'Air, was serving with UN forces in Palestine in 1948, where he commanded a detachment of French peacekeepers. On September 17, 1948 he was traveling by car in Jerusalem, accompanying Bernadotte, now the United Nations Mediator for Palestine. Both were unarmed, as were their bodyguards and Israeli Army liaisons, as Bernadotte wanted to project a peaceful, non-combative image. Their vehicle was ambushed by members of Lehi, who were wearing Israeli army uniforms, intent on assassinating Bernadotte. Both Bernadotte and Serot were killed. The killers were never arrested but the murders led to the discrediting and disbandment of the Stern Gang.
Commando Colonel Sérot (Indochina War)
Capitaine Albert-Charles Meyer, an Armee de l'Air Fusilier-Commando officer, arrived in Indochina in 1951. He set up an intelligence and counter-sabotage unit to defend the airbases of Bien Hoa and Tan Son Nhut. He used native auxiliaries led by Fusilier-Commandos to patrol the area of operations near the base to prevent sabotage to the planes or raids on the airfields. It also handled informants, infiltrators, and Viet-Minh turncoats who gave information on Viet Minh operations.
The unit, Brigade de Recherches et de Contra-Sabotage (BRCS)) ("Intelligence & Counter-Sabotage Brigade") was dubbed the Commando Colonel Sérot in the slain Colonel's honor. Meyer's father had been Sérot's friend and Sérot mentored Meyer when they worked together in the Resistance.