Mayor of Seoul
He served as a member of the National Assembly from 2004 to 2008. He co-founded the New Progressive Party with Sim Sang-jung, Cho Seungsoo, and other members of the People's Democracy faction of the Democratic Labor Party. He unsuccessfully ran for Mayor of Seoul as a New Progressive Party candidate in 2010. He again served as a member of the National Assembly on behalf of the Unified Progressive Party and the Justice Party in 2012 to 2013. Roh broke with the Unified Progressive Party after allegations that the faction led by the party leader Lee Jung-hee had manipulated the party list to elect members of her own faction into the National Assembly. He, with Sim Sang-jeong and Rhyu Si-min, formed the Progressive Justice Party in October 2012, but in 2013 it became the Justice Party.