Born in St Benoit, near Rambouillet, Île-de-France, France, Robert was the son of the gamekeeper of Baron Henri de Rothschild, a member of the wealthy Rothschild family. As a young man, Benoist served during World War I in the French infantry, then as a fighter pilot in the new Armée de l'Air and ultimately as a flying instructor.
Looking for excitement in the post-war world, Benoist joined the de Marçay car company as a test driver. He then moved on to Salmson and was very successful in cyclecar races before being signed to drive for Delage in 1924. The next year, teamed with Albert Divo, he won the French Grand Prix in the race that claimed the life of Italian racing star Antonio Ascari.
In 1927, driving a Delage 15-S-8, he won the French, Spanish, Italian and British Grand Prix races, earning the season championship title for the French manufacturer. He is the only driver ever to win these major Grand Prix races in the same year and his accomplishment earned him the Legion of Honor from the French government.
When Delage dropped out of racing, Robert Benoist was without a job and was appointed manager of the Banville Garage in Paris. He did occasional races for the Bugatti team, finishing second in the 1928 San Sebastian Grand Prix in Spain. The following year he teamed up with Attilio Marinoni to win the Spa 24 Hours race in Belgium, driving an Alfa Romeo.
Then after a run at Le Mans in a Chrysler he went into virtual retirement. He was tempted back in 1934 to drive sports cars for Bugatti, scoring several good placings before winning Le Mans in 1937 with his compatriot Jean-Pierre Wimille. This time he retired for good, to concentrate on running the Bugatti showroom in Avenue Montaigne, Paris and spending time at his country home in Auffargis in the Yvelines département not far from the capital. When war broke out, he once again enlisted, this time in the French army, attaining the rank of Capitaine.
In addition to Jean-Pierre Wimille, Robert Benoist became good friends with another Grand Prix driver, William Grover-Williams. When World War II broke out and France was occupied, these three race drivers all escaped to England where they joined the Special Operations Executive as secret agents to return to France to assist the French Resistance.
After training, Grover-Williams, now working under the cover-name Vladimir, was dropped into occupied France on May 31st 1942 with orders to start a new network from scratch. Codenamed Chestnut, the primarily aim was to act as a sabotage group to cover for Pierre de Vomécourt's Autogiro network which had been betrayed by Mathilde Carré (La Chatte).
Benoist was then parachuted into France and Chestnut moved its base from the centre of Paris to hus family estate. Together, Benoist and Grover-Williams, began working to establish a number of small cells while awaiting arms and munitions from London.
The end for Chestnut came suddenly in June of 1943 in the wake of the collapse of the large Prosper network. There is no direct evidence that Chestnut was compromised by the hand of Prosper, although Benoist and Grover-Williams were in contact with Francis Suttill and Andrée Borrel, the top people in Prosper. However both networks had used the services of the infamous double agent Henri Déricourt,
Francis Suttill and Andrée Borrel, were arrested by the Gestapo. In August, Benoist's home was raided by the Gestapo and Grover-Williams was captured and executed at the Sachsenhausen concentration camp.
Three days later Benoist, who had been away visiting a mistress, was apprehended by the Germans in Paris. Four members of the Gestapo bundled him into a car and although he was sitting between two of them in the back, he was not handcuffed. He noticed that one of the doors was not shut properly and as the car took a sharp left turn, Benoist dived out and escaped down the Passage des Princes at the northern end of the Rue de Richelieu.
He went to a friend's house to change of clothes before quickly moving to another loaction from where he telephoned his chauffeur to be picked up. However he was forced to abandon this plan and escape across the rooftops. He then contacted the garage where he kept a car for just such an eventuality but the Germans had already removed. Forced to hide out in his secretary's flat, Déricourt arranged a flight to England and, on the 19th August, Benoist was airlifted out by an RAF Hudson.
Benoist later returned to France on a second mission in another Hudson. On October 21st, with orders to set up another new network called Clergyman. Based near Nantes, his aim was to blow up the electricity pylons linking the Pyrenees and Brittany and to attack the rail system around Nantes.
However his radio operator was arrested almost imediately and unable to obtain supplies he returned to England early in February 1944. Just one month later he was back in France once more, this time accompanied by fellow SOE agent, Denise Bloch. Still with the same targets in mind, they re-established contact with Wimille.
Benoist was arrested again on June 18th while visiting his dying mother in Paris. Denise Bloch and Mme Wimille were arrested at another Benoist chateau but Jean-Pierre escaped this by dodging between the cars in the driveway and diving into a stream where he remained submerged with just his nose above the surface until the Germans left. A few weeks later Mme Wimille was awaiting deportion at the Gare de l'Est in Paris, when she spotted a cousin in a Red Cross vehicle. She managed to get in and don a while coat and proceed to hand out sandwiches to her fellow prisoners until she could escape. Denise Bloch was taken to Ravensbrück, where she was executed in February 1945.
Robert Benoist was taken to Büchenwald where he was executed on September 9 1944.
Following Germany's surrender, on September 9, 1945 (the date of the first anniversary of his death) the "Coupe Robert Benoist" automobile race was held in Paris in his memory.
Captain Robert Benoist is recorded on the Brookwood Memorial in Surrey, England and as one of the SOE agents who died for the liberation of France, he is listed on the "Roll of Honor" on the Valençay SOE Memorial in the town of Valençay, in the Indre departément of France.
In his honor, the village of Auffargis named a street after him and it is there in the churchyard cemetery on "Allée Robert Benoist" that fellow pioneer race driver, Ferenc Szisz is buried.