[1][2][3] While studying, Jang joined politics as a volunteer for Kang Kum-sil, who contested for Seoul mayorship under the banner of the then ruling Uri Party in 2006 local elections.

[2] On 1 April 2013, he announced his intention to run as a candidate for a Vice President of the Democratic Unionist Party (DUP),[8] but later lost in preselection.

As one of rare youth politicians in South Korea,[5] his role model is Tony Blair and David Cameron; both started their political careers in 20s and later became the Prime Minister of the United Kingdom.

[3] However, shortly before this, Min Byung-doo, the then MP for the constituency, was excluded from preselection, and announced his intention to run as an independent candidate.

[10][11] On 15 April, Jang received 54.54% and defeated the United Future candidate Lee Hye-hoon,[12] who was the MP for Seocho 1st constituency.