Mr. Hyung Seok Yoon is a partner at D&A LLC. Mr. Yoon is actively engaged in legislative strategy, drawing on his extensive experience in policy-making, legislation, and administrative affairs through his service as a secretary to the Office of the President, the National Assembly, various government agencies, and Bar Associations.

Bar Admissions

• Admitted to Bar, Korea (2017)

Education

• Seoul National University Graduate School (Completed Coursework, PhD in Law, 2020)
• School of Law, Seoul National University (JD, 2017)
• Korea University (BA in Public Administration, 2014)
• Sehwa High School (2010)

Significant Accomplishments

• D&A LLC (2025-Present)
• Policy Advisor to the Minister of Environment (2024-2025)
• DR & AJU LLC (2024)
• Administrative Officer, Office of the Senior Secretary for Civil Society, Office of the President (2022-2023)
• DR & AJU LLC (2020-2022)
• Senior Secretary to Lawmaker Kyung Won NA, National Assembly (2018-2019)
• Secretary to Lawmaker Kyung Won NA, National Assembly (2017-2018)

Professional Activities and Experience

• Represented Samsung C&T in litigation on cost sharing lawsuit with regard to the Seoul Subway Line 9 Third Stage 919 area construction
• Represented Seocho-Gu Office and three other Gu offices in litigation on sanitation workers’ wage issue
• Represented Samsung C&T in litigation on Mapo Raemian-Purugio related defects (general defects)
• Represented Samsung C&T in litigation on Kimpo Punggyeong-Maeul Raemian Hangan 2nd Apt. related defects (general defects/fire doors)
• Represented Gwangmyeong SK Techno Park in litigation on defects (general defects/fire doors)
• Represented Samsung C&T in litigation on indirect cost of World Cup Bridge
• Represented Samsung C&T in litigation on indirect cost of Dongdaemun Design Plaza
• Advised KMACA(Korea Mutual Aid Cooperative Association) on amendment of its articles of incorporation

• 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)