Tziolis was born on February 13, 1985, in Katerini, Macedonia, Greece. He began his playing career at local team Apollon Litochoro. In 2002, he made the big jump to Alpha Ethniki outfit Panionios. At Panionios, he played until 2005, appearing in 61 matches. That year, he moved to Panathinaikos where he was a regular.
In 2009 Tziolis started his first journey across Europe that brought him to Werder Bremen (Germany), Siena (Italy), Racing Santander (Spain), Monaco (French League) and APOEL before coming back to Greece in the summer of 2013 as he signed a three-year contract (+ automatically renewal if he had played at least 70% of team's matches) at PAOK.
In the transfer-window of the winter of 2017 he started the second part of his journey that also brought him outside Europe as he played for Kayserispor (Turkey), Heart of Midlothian (Scotland) and Al-Fayha (Saudi Arabia) before announcing his retirement in May 2020.
Tziolis was capped 75 times for the Greek National football team, scoring two goals.