Alexandros Nikolaidis was born in Thessaloniki on the 17th of October 1979 and he is an athlete of the Sports Club «Αlexander the Great».
He began taekwondo when he was a little child, at the age of 3, after the encouragement of his father. His first big success was in 1996, the gold medal in World Junior Championship of Barcelona.
At Sidney's 2000 Olympic Games, he made his first appearance in Olympics but he was unlucky as he suffered serious injury during the quarter final match and had to quit.
The leading moment in his carrier was the silver medal in the Athens 2004 Olympic Games, in the +80 category. Four years later he got the silver medal in the Olympic Games of Beijing.
Nikolaidis is a graduate of Physical Education department, of the Aristotle University in Thessaloniki and speaks English, Spanish and German. His hobbies are football, basketball and music.