By the beginning of World War II, Sergey Obolensky, a White émigré and holder of the George Crosses, was already not young, being over 40. However, he did not remain on the sidelines when the fight against fascism began. Obolensky appealed to the American government to accept him into the U.S. Army. Knowing of his reputation, he was invited to work in the Office of Strategic Services, the predecessor of the CIA.

As an experienced front-line soldier, Sergey Platonovich trained saboteurs for deployment behind enemy lines. He himself had to master parachuting, shooting various types of weapons, tank driving, and boat handling. In 1943, his unit was ready for a secret mission. They were landed in Sardinia to deliver a letter to General Basso, the commander of the Italian forces, demanding surrender and a switch to the American side. At Obolensky's headquarters, he was met with a surprise: the adjutant of the commander turned out to be Count Greppi, the nephew of the Italian ambassador, whom Obolensky had met in Russia. This aided successful negotiations, and the Italians agreed to support the anti-Hitler coalition.

After this, the scouts returned to base in Algiers, where Obolensky met with the Soviet ambassador. Noticing the George Crosses on his uniform, the diplomat asked, "Why not become Russian again?" Obolensky replied, "Returning to Russia would be a mistake; I am now an American."

A year later, Sergey Platonovich received a new assignment: sabotage in the German rear in France. For his bravery, he was awarded the Military Cross. His group prevented the explosion of a power station in Éguizonne. After May 1945, he was offered to participate in the war against Japan, but he declined, citing his age. In 1947, the Office of Strategic Services was transformed into the CIA, and thus, the Russian émigré was at the origins of its creation.