 The two theses (graduates students then had to submit two theses) that she presented for her "doctorat d'etat", "L'illustration du roman de Barlaam et Joasaph" and a paper on Armenian illuminated manuscripts during the late medieval period, were well-received (earning a "Mention très honorable"), and both of them were awarded with prizes by the Académie des Inscriptions et Belles-Lettres and "Revue des Études Grecques" when they were published in 1937.In 1930, Der Nersessian moved to the United States at the suggestion of her three mentors, Byzantinists Charles Rufus Morey, Albert M. Friend Jr., and Walter Cook, becoming a part-time lecturer at Wellesley College in Massachusetts.She taught art history at Wellesley, quickly gaining a full professorship and later becoming the chairwoman of the Department of Art History and Director of Farnsworth Museum.