He graduated from the School of Dentistry of the National and Kapodistrian University of Athens, and is a member of the Panhellenic Socialist Movement since 1974.

In January 1996, he was appointed as Minister for Press and Public Transport as well as the Government Spokesman, a post that he held until 2001.

On 24 October 2001, he was appointed as Minister for Employment and Social Security, a position that he held until the elections of March 2004.

With PASOK's return to power after the October 2009 elections, Reppas was appointed as the Minister for Infrastructure, Transport and Networks.

On 3 January 2015, it was announced that Reppas would join former prime minister Papandreou in leaving PASOK to found the new Movement of Democratic Socialists.