Filippidis was born on November 26, 1986. He is an athlete of Volos Athletic Club (formerly of Panellinios Gymnastic Club) and, as of August 18, 2005, the Greek record-holder in the pole vault. On that day, he jumped 5.75m in the University Games of Izmir, breaking his own Greek record and winning a silver medal. It marked the fifth time - within two and a half months - that young Filippidis had broken the Greek record. That same year, he won a gold medal in the Mediterranean Games and a silver in the European under-21 competition.
On May 10 of that same year, Filippidis won gold at the Diamond League in Doha, Qatar, with a 5.82m performance, setting a new outdoor Greek record.