He used the principle of Kong-an (Korean: 공안) as a way to lead his disciples to Enlightenment.

At age 25, he received Dharma Transmission from Zen Master Mangong.

Zen Master Jeongang later became the ‘Josil’, or supreme patriarch, of Tongdo Temple when he was 33, the youngest in the history of Korean Buddhism.

Later he acted as Josil in the mediation halls of many famous temples within Korea including; Beobjusa, Mangwolsa, Donghwasa, Beomeosa, Cheonchuksa, Yongjusa and Jeonggaksa.

[5] On January 13, 1975, while giving a Dharma Lecture in the meditation hall at Yonghwa Temple, Beopbo, Zen Master Jeongang asked the audience, "What is the purpose of life and death?".