Yoo was brought into the world as Ahn Yeon-seok on April 11, 1984 in Jinju South Gyeongsang Area, South Korea. In his lesser year in secondary school, Yoo chose to take up acting and followed his sibling, who was concentrating on one more year to enter college, to Seoul and they lived respectively close to the area of Samseong-dong.
While taking acting classes, Yoo met a companion who might later work on the outfit staff of movie chief Park Chan-wook. Recalling that he looked like entertainer Yoo Ji-tae, he called him about trying out for a job. Without passing out his resume, he made his acting presentation as Yoo Ji-tae’s more youthful partner in the acclaimed 2003 film Oldboy.
Upon graduation from Sejong College with a degree in Film Expressions, he continued his acting vocation in 2008 and started utilizing his organization’s suggestion stage name, Yoo Yeon-seok.