Gonios started out as a forward. In the 1969 season he made the top 10 of scorers with 18 goals. Afterwards, he was shifted into the defence, playing both as full back and centre back.
With Panathinaikos, Gonios won four leagus titles (1969, 70, 72, 77) and two Cups (1969, 77). He was a member of the team that reached the 1971 Cup of Champions final in Wembley. He also won the 1977 Balkans Cup as a captain of Panathinaikos.