Traianos Dellas got his start at age 11 in the football academy of Aris in Thessaloniki, and he made his debut in the Greek First Division at age 17, during the 1993-94 season with the colors of Aris FC. He then played for Panseraikos for two years, before returning to Aris.

In the summer of 1997, he joined Sheffield United in the UK, kicking off his international career. In the summer of 1999, he was acquired by AEK FC, where he stayed until the summer of 2001, winning the Greek Cup in 1999-2000.

His next stop was Perugia, in the Campionato, where he played a total of eight matches. In May 2002, he continued his career in Roma, where he stayed until the summer of 2005. In 2005, he returned to AEK, where he stayed until 2008, when he agreed to move to Anorthosis. In the summer of 2010, he returned to AEK for the 3rd time, where he stayed until 2012, finishing his career there.
He made his debut with the Greek national team in April 2001.

The highlight of his career with the Greek national team was when he scored a goal in the Euro 2004 semifinal against the Czech Republic on July 1st, 2004 and winning the European Championship three days later, while participating as a starter for the full 90 minutes in all six matches of the Greek team.

He was AEK Athens’ coach from 2013 to 2015 and then the coach of Atromitos until 2016. From January 2018 until the end of the ’18-19 season he was the coach of Panetolikos.

He has been married since 2008 and has a daughter.