He is a four-time[2] Skeet Shooting medalist in the World Championships, and a four-time[3] Olympian, with his 5th position in Beijing 2008 being to date (as of 2017) Cyprus’ third-best all time placing[4] at the Olympics, after Pavlos Kontides’ silver medal in Laser sailing in London 2012 and Antonis Nikolaidis’ 4th place in Skeet Shooting in Beijing 2008.

Achilleos has the existing distinction of being the inaugural Cypriot athlete to set a World Record in an Olympic Sport.

He started competing in Skeet Shooting in a young age and recorded his first success in the Junior level.

Just a few months before turning 20, George Achilleos was named a member of Team Cyprus at the 2000 Summer Olympics, held in Sydney.

Ten shooters tied at 122/125 for the remaining three spots in the final, amongst them fellow Cypriot Antonakis Andreou, who went on to take 8th place.

The Cypriot delegation received a standing ovation by the mostly Greek crowd, due to the islands’ ties to Greece.

Due to his international successes, Achilleos was chosen for a second consecutive Olympiad to carry the flag at the Opening Ceremony, this time in the Bird's Nest of the Chinese capital.

A week later (15 and 16 August) the skeet event was set to take place and all Cypriot eyes were on the Beijing Shooting Range.

Fellow Cypriot Antonis Nikolaides also finished the qualification round in the top 6, with a score of 120/125, giving Cyprus its first ever double Olympic final participation in any event.

The 4th and 5th position by Nikolaides and Achilleos respectively is to date (as of 2017) Cyprus’ second and third best placing in the Olympics, following the silver medal of sailor Pavlos Kontides in London four years later.

On day 2 Achilleos was improved with a total of 49/50, but the 118 mark was two discs below the needed score to qualify for the final, finishing in 11th position.

Achilleos shot a perfect 125/125 two more times during domestic championships, although these particular events didn't count for a world record.

[11] Achilleos was selected as the flag bearer of Cyprus for the opening ceremony of the 2014 Commonwealth Games in Glasgow at Celtic Park.

Achilleos travels each year after the end of the season to the Beretta factory in Brescia, Italy for modifications to his weapons.