Hellenic Military Academy
Born in Volos, Greece, Gizikis was a career Hellenic Army officer. He graduated from the Hellenic Military Academy in 1939, achieving the rank of second lieutenant in artillery, and participated in the Greco-Italian War and the Greek Civil War. In 1967, he supported the Georgios Papadopoulos coup d'état and received a number of senior military posts during the dictatorship that followed.