Acting MayorⅠ for Administrative Affairs, Joon Byeong Yoon has worked for the Seoul Metropolitan Government of Republic of Korea for the past 35 years. In 2017, he has overseen Seoul city planning, organization, external cooperation etc. as Director of Planning and Administration office. Since 2018, he has led the Department of Seoul Administrative Affairs especially by taking advantage of his decades of professional experience in the Headquarter of City Transportation. As Vice-Mayor, Joon Byeong Yoon now manages Women & Family Policy Affairs Office, Emergency Planning Bureau, Information System Planning Bureau, Special Enforcement Division for Public Safety, and Employment & Labor Policy Bureau.