[1] Yon was educated in Czechoslovakia and by the 1950s, he was firmly established within the hierarchy of the Workers' Party of Korea.

During this era, Yon served as Minister of Heavy Industry and this consolidated his role in the North's large armaments sector.

In this period, as Kim Il Sung and O Jin-u were both already past eighty, Yon took an important role in relations between North and South Korea.

By the 2000s, Yon was declining in health and his role in North Korean politics had become largely ceremonial by the time he died - presumably of pancreatic cancer for which he had received treatment in Russia in 2004 at the well protected Central Clinical Hospital.

Yon was a recipient of the Order of Kim Il Sung, Hero of Labor and other awards.