Sofianidis was born on August 3, 1937 in Istanbul where he played for Pera Club FC before joining Besiktas JK. He came to Greece in the late 1950s and joined AEK. He was their regular left back until 1969. Sofianidis retired after the 1970 season as a player of Panachaiki. During his career, he played 240 Alpha Ethniki games and was capped 7 times by the National Football Team of Greece.
After his playing career was over, Sofianidis coached several teams, including the Greek National Football Team (1989) and the Under-17 National Football Team. He was a gymnastics teacher by profession.
Did you know?
When AEK played Fenerbahce in the Balkan Cup of 1968, Sofianidis did not accompany his club to Istanbul as he would have been liable of arrest by the Turkish authorities for not fulfilling his military obligations.