Mr. Sang Hyuk YOON is a partner at D&A LLC. His practice is primarily focused on Criminal & Compliance (C&C), Trials, Elections & Regulations, and Risk Advisory, Internal Investigations & Digital Forensics.

Mr. Yoon brings extensive experience and expertise from his tenure as a prosecutor at the Corruption Investigation Office for High-ranking Officials. He managed investigative planning and corruption-related crime investigations, serving as an Investigation Planning Officer and working at Investigation Departments I, II, IV, and the Prosecution Department. He was recognized as an Excellent Prosecutor for his exemplary work in maintaining public prosecutions in election-related cases. In addition, he gained extensive experience and expertise by participating in numerous search and seizure operations during his tenure as a prosecutor.

Bar Admissions

• Admitted Bar, Korea (2015)

Education

• Kyung Hee University Law School (JD, 2015)
• Korea University (BA in Sociology and LLB, 2010)
• Kyungbock High School (2000)

Significant Accomplishments

• D&A LLC (2024-Present)
• Prosecutor, Corruption Investigation Office for High-ranking Officials (2022-2024)
• Grade V Prosecution Official, Corruption Investigation Office for High-ranking Officials (2021-2022)
• D&A LLC (2016-2021)
• HANBYOL LAW, LLC (2015-2016)

Professional Activities and Experience

• Investigated and maintained public prosecution in multiple cases involving abuse of authority and obstruction of the exercise of rights
• Investigated and maintained public prosecution in multiple cases involving violations of the Public Official Election Act
• Represented lawmakers suspected of violating the Public Official Election Act during investigations and hearings
• Represented heads of local government suspected of violating the Political Funds Act during investigations and hearings
• Represented multiple companies suspected of violating the Punishment of Tax Offenses Act during investigations and hearings
• Represented multiple public officials and executives of redevelopment and reconstruction associations suspected of involvement in bribery during investigations and hearings
• Represented multiple companies suspected of embezzlement and breach of trust during investigations and hearings

• Legislative Reform of the Petition System - Insights from the Yoon Seok-yeol Administration's National Proposal Initiative - Journal of Legislative Studies, Vol. 22, No. 2 (Korean Society of Legislation Studies, 2025)
• Online Petition System of the Blue House as a New Communication Platform - Focusing on the status and legal institutional improvements - Law and Policy, Vol. 27, No. 2 (Jeju National University Institute of Law & Policy, 2021)
• Legislative Issues in Ensuring the Right to Petition - Focusing on the Online Petition System of the National Assembly of Korea- Journal of Legislative Studies, Vol. 17, No. 2 (Korean Society of Legislation Studies, 2020)
• The Unconstitutionality of the Blackout Period on Pre-Election Polls and Legislative Alternatives, Journal of Media and Law, Vol. 18, No. 3 (Korea Press Law Association, 2019)