He is a member of the National Assembly for Seo District, Gwangju since 2015, having previously represented Ansan from 1996 to 2012.

[2] After standing unsuccessfully for a seat in Seoul in the 2012 elections for the Democratic United Party, Chun organized the presidential nomination campaign of Kim Doo-kwan as an alternative candidate to Moon, who would become the party's nominee.

He ran as an independent that year in a by-election in Gwangju, commonly viewed as a stronghold of the main liberal party, and defeated the NPAD candidate in a shock landslide victory on April 29, returning to the Assembly.

[7] In the lead-up to the 2016 parliamentary elections, however, Chun came into conflict with Ahn in March over the prospect of an electoral alliance with the Minjoo Party of Korea, the NPAD's successor; Chun vowed to boycott party meetings until Ahn withdrew from his opposition to such a pact.

[8] He backed down after a private meeting with Ahn on March 15,[9] and the alliance with the Minjoo Party ultimately failed to materialize.