Athanassoulas started his rally career in 2001. In 2005 he won the A5 class of the Greek rally championship. He also made his debut in the World Rally Championship (WRC) in 2005 . He took part in the Rally Greece in a Ford Fiesta . In 2006 he competed in six WRC rallies. In 2007 he changed his vehicle and competed in a WRC rally in a Subaru Impreza that year and the following year . In 2009 Athanassoulas took part in two rallies. First he started in the Škoda Fabia in the Rally Greece. The rally driver finished eighth and scored his first point in the WRC. He also won the PWRC ranking. Later he only took part in one other WRC rally in a Ford Fiesta. At the end of the season he finished 20th in the world championship. In the PWRC classification, Athanassoulas finished ninth overall. At the 2011 Rally Greece he started in a Ford Fiesta RS WRC and finished 19th overall at the end of the rally.