He came from a relatively prosperous family and went on to study law in Athens, but before being able to graduate, he was arrested and jailed in the Akronauplia prison (Nauplion) by the Ioannis Metaxas regime in the 1930s and transferred to the Germans after the Axis occupation of Greece (1941).

After becoming Political Commissioner of the Democratic Army of Greece (DSE) during the Greek Civil War, he was one of the last to leave the country (1949) after its defeat.

Beloyannis denied all accusations and stressed the patriotic nature of his actions during the anti-Nazi resistance (1941—1944), the British intervention (1944–1946) and the Greek Civil War (1946–1949).

[9] The manuscripts of the former were published in 2010 under the title Foreign Capital in Greece (Το Ξένο Κεφάλαιο στην Ελλάδα, To Kseno Kefaleo stin Ellada).

[10] Through the detailed analysis of Greece's external borrowing, its history is presented as one of subjection to foreign powers and financial institutions who ended up controlling most of its economy and resources to the dismay of the working class.