Kim San was born on April 14, 1905, in Ryongchon County, North Pyongan Province, Korean Empire.

Since then, like many of his Korean contemporaries, he became a Socialist revolutionary not only with this experience of colonial agony, but also under the radicalizing influence of the Russian Revolution in 1917.

He attended Whampoa Military Academy and was enrolled in the department of medicine and later in the political science at Sun Yat-sen University.

He participated in armed battles such as the Guangzhou Uprising in 1927 on the side of the Chinese Red Army risking his life several times.

He also lectured Chinese Red Army members physics, chemistry, mathematics, Korean and Japanese courses at the Military and Political Academy for Fighting against Japan in Yan'an, China in 1937.

[1] American journalist Nym Wales, who was then Edgar Snow's wife, met him as she was curious of him because she learnt that many of the books written in English that she wanted to borrow from Lu Xun Library has been already borrowed by him, and interviewed him more than 22 times for three months from June to August 1937 at the library in Yan'an, while interviewing key Chinese revolutionaries including Mao Zedong.

He was reinstated by the Central Committee of the Chinese Communist Party in January 1983 after his son had requested the recovery of his father's honor in 1978.