Graduating from Korea University in 1983 with a bachelor degree in law, Oh Se-hoon was admitted to the Korean bar and continued his education at the same institution, achieving a masters in commercial law in 1990, and earning a doctorate (civil procedure) in 1999.

Oh launched his legal career in 1991 and gained experience in a variety of roles – lawyer, professor and legal advisor. During this period, he also participated actively in many national committees on diverse subjects such as environmental issues, policy and the arts.

Oh Se-hoon was inaugurated as 33rd Mayor of Seoul in 2006 and immediately declared his intention to transform Seoul into a truly global city and the commercial hub of Asia.