Korean pro (b. 1985-7-15), pupil of Kweon Kap-yong was promoted to 1 dan in 1998 and to 6 dan in 2004. Also spelled Won Seong-Jin 원성진
Won was promoted to 9 dan in 2007 when he won the 17th BC Card (Korean New Stars), then the 12th Chunwon.
Semifinalist in the 7th (2002-03) LG Cup (when he was only 4 dan). He was knocked out by Lee Changho, who went on to win the tournament over Lee Sedol.
In 2008 he beat Gu Li in the 12th China Korea Tengen,.
In 2010 Won reached the final of the 38th Myungin, losing to Park Yeonghun 3-2; in Korean ranking at the end of October he reached #2.
Winner of the 15th GS Caltex Cup, beating Cho Hanseung 3-1.
Winner of the 16th Samsung Cup in 2011, defeating Gu Li 2-1.
He won every single one of his seventeen (!) games in the 2020-21 season of the Korean Baduk League, as a member of the Celltrion team. For this feat, he was named the season's MVP.