[1] Yoon was killed on the last day of the uprising and has since become a symbol in South Korea as a martyr for the democratization movement.

Opposed to the military dictatorship under Park Chung Hee, Yoon quit his job at a bank in 1978 to focus on democracy activism.

[1] Yoon worked on organizing labour groups and helped form the National Democratic Workers’ League on May 1, 1980.

On May 18 of that year, a citizen's uprising against military rule and Coup d'état led by Chun Doo-hwan broke out in Gwangju and Yoon quickly became the leading spokesperson of the organizing Democratic Struggle Committee.

Yoon and the remaining militia members took up residence in the main building of the Jeonnam Provincial Office [ko] which was turned into the de facto headquarters of the resistance.