In the summer of 2008, Christodoulopoulos was acquired by Panathinaikos. His career with the greens lasted until January 2013 when he signed for Bologna in the Italian Serie A. The following year, he moved on to Hellas Verona. He played the 2015 - 2016 season on loan to Sampdoria and, at the end of that season, returned to Greece to play for AEK.
He made his debut with the senior side on February 5, 2008, in a 1-0 friendly win over the Czech Republic, coming on as a substitute for Giorgos Samaras. So far Christodoulopoulos has been capped 28 times and scoring one goal.