Stephanos N. Koumanoudes was born in Athens in 1931. His great grandfather was Stephanos A. Koumanoudes, the eminent Greek archaeologist and epigraphist, Professor of Latin Philology at the University of Athens from 1845 until 1886 and Secretary of the Archaeological Society at Athens from 1859 to 1894.

Stephanos the younger, as he was known to his fellow epigraphists, archaeologists and classicists, studied Greek Philology at the University of Athens (he graduated in 1954) where he also attended courses in Greek History and Archaeology for two years.

Having received a three year scholarship from the State Scholarships Foundation, he pursued graduate studies in France at the École Pratique des Hautes Études and at the Collège de France. He was a student of Louis Robert (Greek Epigraphy and Numismatics), of A. Aymard (Ancient History), of A. Bataille (Greek Papyrology), of P. Chantraine (Linguistics) and of P. de la Coste-Messelière (Greek Sculpture and Architecture).

For many years he taught Ancient Greek to high school and university students. He participated in the work for the exhibitions of the Akropolis, Eleusis and Epidaurus Museums. He undertook excavations and published the results of a small excavation at Rhea in Attica.

Between 1966 and 1968 he was appointed lecturer of Ancient Greek at the University of Athens.

He was a founding member of the Society for the Study of Greek Civilization which published the journal Neon Athenaion (1955-1967).

Between 1968 and 1970 he was Director of Antiquities in the Greek Archaeological Service of the Greek Ministry of Culture.

In 1972 and between 1975 and 1977 he offered free courses on Greek Epigraphy and Attic Topography to University students of Classical Archaeology.

In 1985 he founded the Greek Epigraphic Society along with Al. N. Oikonomides, Athena G. Kalogeropoulou and a few other junior scholars.

In April 1986 he delivered an inspiring speech expressing his dedication to the study of Greek Antiquity and its importance for the future of Greece. In May of the same year he underwent heart surgery and a year later (3 July 1987) he died unexpectedly at the age of 56.