Kim Woo Seok, also known by his stage name Wooshin, is a vocalist, visual, and the first member of the boy group UP10TION under company TOP Media. He had been training for a year before joining the group. He is a graduate of Dong-ah Institute of Media and Arts with major in K-Pop and acting. He is also a model and host.

He and Somi from I.O.I were hosts on the sixth season of music television program The Show from October 11, 2016 to April 25, 2017. On June 6, 2017, TOP Media issued a statement regarding Wooshin's hiatus in UP10TION. It was stated that his psychological condition had worsened due to the mental stress that he had been receiving since the end of 2016. Wooshin returned to the group activity when UP10TION had their comeback on March 15, 2018.

After training for four years and seven months, he made his appearance as a contestant on boy group survival reality show Produce X 101. He ranked 2nd in the final episode of Produce X 101 and became a member of boy group X1.