Ioannidis is a product of the youth academies of Iraklis and started his professional career at the first team in 2006.

[1] On 22 July 2010, Ioannidis moved to Panathinaikos on a free transfer, signing a three-year contract.

[3] On 21 January 2019, AE Lefkimmi announced the signing of Ioannidis.

[4] Ioannidis was a member of the Greek under-19 team who reached the final of the 2007 European under-19 championship against Spain, a game which they lost 1–0.

[5] He was also a member of Greece under-21, as he made 12 appearances and scored one goal for the team against Macedonia under-21.