Jeong was born in 1546 to a yangban (noble) family in Jeonju-bu, North Jeolla Province.
His criticisms caused the displeasure of King Seonjo, who compared him to Xing Shu (邢恕) of the Song Dynasty who was widely believed to have betrayed his teacher, Cheng Hao.
[1] Following this, he resigned from the government and returned to his hometown, Jeonju, where he conducted academic research and formed an armed organization, Daedonggye (대동계; 大同契), to oppose Japanese pirates.
In 1587, the Daedonggye was powerful enough to defeat a group of pirates when the Jeonju magistrate's governmental army could not.
In 1589, as a result of the reported rebellion, he fled to Jukdo Island, and committing suicide when government forces closed in on him.