In Sung Yoon is an attorney at Kim & Chang. Mr. Yoon joined the firm in 2014, where he practices in the areas of administrative litigation, fair trade litigation, civil case and criminal defense. 

Before joining Kim & Chang, Mr. Yoon served in the judiciary for 20 years, first as a judge advocate at the Republic of Korea Navy and later as a judge at the Supreme Court of Korea, Seoul High Court, and Seoul Administrative Court, among others. 

In 2006, Mr. Yoon worked at the 7th administration department of the Seoul High Court, which was exclusively in charge of fair trade cases. From 2007 to 2008, he researched a significant volume of cases related to fair trade law and administration law as a judicial researcher in the constitution administration group of the Supreme Court. Mr. Yoon then acted as a presiding judge at the Daejeon District Court and, from 2010 to 2013, was a judicial researcher and a chief judicial researcher of the constitution administration group at the Supreme Court. Throughout his career, Mr. Yoon has continuously reviewed cases related to fair trade law and administrative law and conducted extensive research in these areas. 

After the completion of his position at the Supreme Court in 2013, Mr. Yoon handled a number of administrative cases as a presiding judge at the Seoul Administrative Court, which specializes in administrative matters. 

Mr. Yoon was also a member of the Cartel Policy Advisory Committee at the Korea Fair Trade Commission from 2009 to 2013. When he was a chief judicial researcher of the constitution administration group at the Supreme Court, he was also a member of the Administrative Trial Committee at the Office of Court Administration. 

Mr. Yoon published several case reviews and research papers on administrative law and fair trade law, which have included publications on the topic of fair trade law in the Journal of Competition. He is currently a member of the Korea Public Administration Case Study Association, Korea Competition Law Association, and Society of Economic Law Case Study. 

Mr. Yoon passed the 33rd Korean Judicial Examination in 1991 and graduated from Seoul National University College of Law in 1992. In 1997, he graduated from Graduate School of Law, Seoul National University with a master’s degree in economic law. He continued his studies at University of Cambridge Faculty of Law focusing on fair trade law from 2002 to 2003.