In 1585 Jeong passed a gwageo for the selection of officials and became an officer of the military training department of Hanseong (hanseongbupanyun).
In 1590, he was appointed as an inspecting officer at Saheonbu (Saheonbujipyeong), also serving as a member of King's assistant group.
In the next year, he was dispatched to the northeastern border as a crops commander of this region.
They totally reclaimed the northeastern province by winning at Baegtapgyo in the next year.
In 1624, he died while being tortured after he was arrested and falsely accused of participating in a revolt of Yi Gwal.