Chatzitheodoridis is a product of the Arsenal academy and played senior football in England for Brentford and Cheltenham Town, before returning to Greece to join Panathinaikos in 2018.
[8] An injury crisis at left back saw Chatzitheodoridis win his maiden first team call up for a league match versus Wolverhampton Wanderers on 24 September 2016, but he remained an unused substitute during the 3–1 defeat.
[9] The departure of second-choice left back Tom Field on loan for the first half of the 2017–18 season allowed Chatzitheodoridis to make his senior debut with a start in the Bees' 3–1 EFL Cup first round extra time win over AFC Wimbledon on 8 August 2017.
[11] He played the full 90 minutes of the 4–1 victory over rivals Queens Park Rangers in the following round and on 7 September,[11] manager Dean Smith reported that Chatzitheodoridis would begin training with the first team on a regular basis.
[12] A season-ending injury to Rico Henry in late September saw Chatzitheodoridis become the backup to stand-in left backs Josh Clarke and Yoann Barbet during the first half of the 2017–18 season.