He excavated widely, particularly at Olynthus, Eleusis and Mycenae, where he made the first archaeological study and publication of Grave Circle B, the earliest known monumentalized burials at the site.

He witnessed the destruction of Smyrna in September 1922, and was subsequently taken prisoner; he was recaptured after a brief escape, but was released in 1923 after bribing his captors with money sent by his American contacts.

At the same time, his belief that ancient Greek mythical traditions, particularly concerning the Trojan War and the Eleusinian Mysteries, could be verified by archaeological excavation was controversial in his day and has generally been discredited since.

[9] Alexander MacLachlan, a witness to the city's destruction, recalled seeing Mylonas deliver a Christian service in Greek on the morning of Sunday, September 10 [O.S.

[8] After escaping from the camp at Smyrna in early March 1923, he obtained passage on a French merchant ship, whose crew handed him back to the Turks.

[11] He was helped to survive by American friends, his former teachers at the International College,[12] who lent him money to pay bribes and secure his release.

[15] The ASCSA had assisted in the evacuation and resettlement of Greek refugees from Ionia and employed many of them in the construction of its Gennadius Library, conducted under the architect W. Stuart Thompson between September 1923 and 1925.

[22] In 1928, he resigned from his bursary post at the ASCSA and emigrated to the United States to study at Johns Hopkins University in Baltimore under David Moore Robinson, the excavator of the classical site of Olynthus in the Chalkidiki region of northern Greece.

[24] Mylonas was awarded his second Ph.D. by Johns Hopkins in 1928; his dissertation was published as the first volume in the series presenting the results of the Olynthus excavations.

[28] Mylonas returned to the United States later in 1931: he was hired by William Abbott Oldfather, the dean of the University of Illinois at Urbana-Champaign, as a temporary assistant professor on an annual salary of $2,200 (equivalent to $40,126 in 2023).

[2] In 1933, Mylonas was hired on a permanent basis at Washington University in St. Louis as an assistant professor in the Department of Art History and Archaeology.

[39] Simultaneously, he served as an annual professor at the ASCSA;[40] following the suggestion of the chairman, Charles Morgan, that a vice-chairman be appointed in case he was called for military service, Mylonas was given the position.

[37] On December 22, 1951, he visited, along with John Papadimitriou, what would become known as Grave Circle B at Mycenae,[43] which had been discovered that November by the ephor Seraphim Charitonidis during restoration of the nearby Tomb of Clytemnestra.

Papadimitriou was appointed to lead the excavation, and himself organized a committee of archaeologists, consisting of Mylonas, Charitonidis, Antonios Keramopoulos and Spyridon Marinatos, to oversee the work.

[56] He also investigated the site's Cult Center,[55] to which he gave its modern name on the grounds of his interpretation of the structure as a focus for religious ritual.

[57] Mylonas held a Fulbright Professorship at Athens in 1954,[58] and spent periods throughout the 1950s at the Institute for Advanced Study in Princeton, New Jersey.

[59] He served as president of the Archaeological Institute of America between 1957 and 1960,[21] becoming the first foreign-born person to hold the post,[60] and held a visiting professorship at the ASCSA in 1963–1964, during which he conducted a tour of Crete and offered a course in Mycenaean civilization.

In an interview conducted at the citadel of Mycenae, Mylonas spoke of coming to the site by night to converse with the mythical king Agamemnon.

[34] Mylonas met Lena Papazoglou, another Greek refugee from Ionia, shortly after his return to Greece in 1923; the couple married in 1925.

[78] The archaeologist Diamantis Panagiotopoulos has called Mylonas's 1927 dissertation the first publication to systematically synthesize the Neolithic material from the Greek mainland and the island of Crete.

[60] Vogeikoff-Brogan has called Mylonas a pioneer in archaeological fundraising; without the large institutional budgets of colleagues like Blegen, Mylonas cultivated relationships with wealthy members of St. Louis society, encouraged his financial supporters to visit and participate in his excavations, and reported his work energetically in the St. Louis local press.

[37] During his time at Washington University, Mylonas established the philanthropic Mycenaean Foundation with support from American friends and students.

The foundation opened an archaeologists' hostel, known as McCarthy House, and a cultural center and medical clinic, known as the Mycenaean Melathron, in the village of Mykines in 1969.

[37] Mylonas believed in the essential historicity of the Greek mythical tradition; in his work on Mycenae, he attempted to establish chronological dates for the reign of Agamemnon and the Trojan War.

[84] A contemporary review of his 1966 book, Mycenae and the Mycenaean Age, described his practice of using the mythological tradition to reconstruct historical events as "a dangerous procedure at best".