Born in Alexandreia, Greece, he began his career at the academy at AE Alexandris and later the team of Naoussa, which also produced players such as Vassilis Lakis and Dimitris Markos. While playng for Naousa, he aroused the interest of the big teams, mainly AEK Athens and Panathinaikos. In the end, in December 1992, he was transferred to AEK. After the first 1.5 years, which was a period of adjustment and was between substitutes and starters. However Tsiartas, showing direct examples of his rare class with a characteristic debut on 12/12/1992, which he scored 2 goals in a 7-0 victory against Korinthos in Nea Filadelfeia, made permanent in the team starting lineup during the 1994-1995 seaspn. This season he had a very good presence in the matches for the Champions League, while he also made several very good appearances in domestic competitions. The period 1995-1996 Tsiartas was probably the best of his career in Greece, since he became the top scorer of the Greek championship with 26 goals in 33 league matches, achieving and many impressive goals, while he also scored many assists for his teammates. For the specific season, he also scored 7 goals in the Cup, which AEK won in the end, while he was voted the best Greek football player of the league (alongside Karapialis and Donis) by his colleagues in the league. Tsiartas soon made a name for himself and his subsequent move to AEK Athens resulted in him scoring the most goals in the 1996 season in the Alpha Ethniki.