Mr. Heo began his career as a prosecutor in 1997 at the Gwangju District Prosecutors’ Office and served as a prosecutor of the Chungju branch of the Cheongju District Prosecutors’ Office, Office of Deputy Director General of Legal Affairs under the Ministry of Justice, and the Seoul Central District Prosecutors’ Office. He was also a deputy senior prosecutor of the Ulsan District Prosecutors’ Office and the Seoul Southern District Prosecutors’ Office, and a senior prosecutor of the Narcotics and Organized Crime Department of the Changwon District Prosecutors’ Office’s Tongyeong branch and the Suwon District Prosecutors’ Office.
Furthermore, Mr. Heo held numerous key posts of the prosecution, such as the head of the Narcotic Department of the Supreme Prosecutors’ Office, and a senior prosecutor of the Criminal Department of the Seoul Northern District Prosecutors’ Office, the Seoul Central District Prosecutors’ Office, the Changwon District Prosecutors’ Office, and the Seoul Eastern District Prosecutors’ Office. He also headed the International Cooperation Center of the Supreme Prosecutors’ Office and served as a chief prosecutor of the Changwon District Prosecutors’ Office prior to his appointment as the head of the Changwon District Prosecutors’ Office’s Masan branch.