In Greece, he was a fellow at the American School of Classical Studies at Athens (1911–1913), during which time he worked on excavations at Locris, Corinth and Korakou. During World War I Blegen was involved in relief work in Bulgaria and Macedonia, receiving the Saviors Order from Greece in 1919. Following the war he completed his Ph.D. at Yale (1920). He was then assistant director of the American School (1920–26); during his tenure he excavated at Zygouries, Phlius, Prosymna, and Hymettos. In 1927, Blegen joined the faculty of the University of Cincinnati. Blegen was professor of classical archaeology at the University of Cincinnati from 1927–1957. His excavations at Troy were carried out between 1932 and 1938, followed by those at the Palace of Nestor in Pylos, Greece in 1939 (the dig resumed 1952-1966). Many of the finds from this excavation are housed in the Archaeological Museum of Chora. Blegen retired in 1957.