Culbertson was born in Poiana Vărbilău in Romania to an American mining engineer, Almon Culbertson, and his Russian wife, Xenya Rogoznaya. He attended the École des sciences économiques et politiques at the Sorbonne in Paris, and the University of Geneva. His facility for languages was extraordinary: he spoke Russian, English, French, German, Czech and Spanish fluently, with a reading knowledge of five others, and a knowledge of Latin and classical Greek. In spite of his education, his erudition was largely self-acquired: he was a born autodidact.