Maropoulos came to Greece with his family at age 3 - after the Asia Minor Disaster and settled in Kalamata. At age 12 he joined the local football club Prasina Poulia. When his parents moved to Kalogreza in the Athens area, he signed for Ethnikos Kalogreza. In 1934, he was spotted by AEK who placed him in their youth team. In 1936, he was promoted to the first team.
Unfortunately, the glory years of AEK and Maropoulos were interrupted by the World War II. He continued his career after the war and played until 1952. He is credited with scoring 253 goals, 97 of which he attained prior to the war.
Maropoulos was capped 10 times by the National Football Team of Greece. He subsequently managed the Greek National Team in the early 1960s before retiring altogether from football to manage his sporting goods stores. He died in 1991.