He was married to Dr. Angeliki Laiou, a Harvard professor who was a scholar of Byzantine empire, and the second woman to be named a permanent member of the Academy of Athens since the organization was founded in 1926.
Syrgiannes's ambition, inveterate plotting, and multiple betrayals made him one of the darkest figures of the era in the eyes of both contemporary and later historians: the 14th-century historian Nikephoros Gregoras compared his flight to Serbia with Themistocles's flight to the Persians, while Donald Nicol likened him to Alcibiades and Angeliki Laiou called him "the most evil presence" of the civil war.