After graduating, he worked at a Hyundai Motors' manufacturing plant located in Jeonju.

There, he served as the President of the Hyundai Motors contracted workers branch of the Korean Confederation of Trade Unions.

[3][4] He ran as the Progressive Party's candidate for a by-election held for the Jeonju B constituency of the National Assembly.

He won the election with 39 percent of the vote, becoming the Progressive Party's first National Assembly member.

[5] On 18 January 2024, Kang was forcefully carried out and removed by presidential security agents at a ceremony launching North Jeolla Province as a special self-governing province after verbally urging President Yoon Suk-yeol to "change [his] approach to governance.