Chang was firstly elected for the National Assembly representing Sasang District in
2008 election, During this time, the ruling
Saenuri Party underwent some conflicts in
preselection, as the main opposition
Democratic Unionist Party (DUP) selected
Moon Jae-in, one of the potential presidential candidates at that time, for Sasang District. Chang returned as an MP after the
2016 election. Originally, he intended to run under the Saenuri banner. After Son was re-selected, Chang left the party and won as a nonpartisan candidate. He then returned to the party on 21 June. During the
political scandal in the late 2016, Chang was one of hearing members from the Saenuri Party (LKP since February 2017) along with Kwon Seong-dong and
Hwang Young-cheul. He then left the party with another 30 MPs and formed the
Bareun Party. Nevertheless, prior to the
presidential election in May 2017, he returned to the LKP and endorsed its presidential candidate,
Hong Joon-pyo. On 22 March 2018, Chang provoked a controversy when he called the police "government's hounds infected with
rabies" after they launched an investigation related to
Kim Ki-hyun, the then Mayor of
Ulsan, who was also a member of the LKP. He also asked to "hit the mad dogs". == Personal life ==