Born of an English father and a French mother in the Montrouge suburb of Paris, France, William Grover-Williams grew up fluent in both the French and English languages. When World War I broke out, his family moved to Monaco where he got a job as a chauffeur. Mechanically inclined, and fascinated by motorized vehicles, Grover-Williams bought a motorcycle and began racing. Returning to Paris, in 1919 he worked as the chauffeur for the famous Irish war artist Sir William Orpen (1878-1931).
By 1926 William Grover had begun racing a Bugatti car in races throughout France, entering the Grand Prix de Provence at Miramas and the Monte Carlo Rally. In 1928 he won the French Grand Prix, repeating that feat again in 1929. That same year, driving a Bugatti 35B, painted in what would become known as British racing green, he won the inaugural Monaco Grand Prix beating the heavily favored Mercedes car driven by the great German driver, Rudolf Caracciola.
In November of 1929 Grover-Williams married Yvonne Aubicq, Sir William Orpen's former mistress whom he had met when chauffeuring the two around Paris. Successful financially, they maintained a home in a fashionable district of Paris while owing a large house in the resort town of La Baule in the Pays de la Loire on the Bay of Biscay which was home to one of the annual Grand Prix races. In 1931 he won the Belgian Grand Prix and he won the Le Baule Grand Prix three consecutive years from 1931 to 1933 but after that his career waned and he was out of racing by the latter part of the 1930s.
Following the Nazi occupation of France in World War II, Grover-Williams fled to England where he joined the Royal Army Service Corps as a driver. Because he was a French citizen and because of his fluency in both languages, he was recruited into the Special Operations Executive of the French Resistance working with two other French Grand Prix race drivers, Robert Benoist and Jean-Pierre Wimille. In May of 1942, he was parachuted into France where he made his way to a small apartment in the Trocadero in the 16ème arrondissement, Paris. Grover-Williams worked in the Paris region to build up a successful circuit of operatives, forming sabotage cells and reception committees for parachute operations.
In June of 1943, William Grover-Williams was arrested by the Gestapo and shipped to the Sachsenhausen concentration camp outside Berlin, Germany. There, prisoners died in violent medical experiments or were executed. Nearly 100,000 people died from exhaustion, disease, malnutrition and pneumonia. In the Spring of 1945, prior to the liberation of the camp by Allied forces, the SS forced the prisoners to march to other camps further west. Most of the totally exhausted prisoners did not survive this last march; collapsing prisoners were shot by the SS guards. Among those executed only weeks before the war's end, was William Grover-Williams.
William Grover-Williams 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.