Kim Go-eun made her debut in the 2012 South Korean erotic film ‘A Muse,’ directed by Jung Ji-woo. Kim’s performance as ‘Han Eun-gyo’ in the film earned her several awards, including the ‘Buil Film Award,’ ‘Grand Bell Award,’ and a ‘Blue Dragon Film Award.’ In 2014, she starred as ‘Bok-soon’ in the Hwang In-ho-directed South Korean action thriller film ‘Monster.’ The film had the critics divided with some praising the combination of thriller and comedy elements while others terming it as "unharmonious" and "almost schizophrenic." The following year, she appeared in the film ‘Coin Locker Girl,’ directed by Han Jun-hee. Kim portrayed ‘Ma Il-young’ for which she bagged the ‘Korean Film Actors' Guild Award.’
In 2016, she made her television debut in the South Korean romance drama television series ‘Cheese in the Trap.’ That same year, she also starred in the fantasy drama television series ‘Guardian: The Lonely and Great God.’ She played the role of ‘Ji Eun-tak’ and remained a part of the series until it went off-air in 2017. Kim was next seen in the role of ‘Sun-mi’ in the 2018 South Korean drama film ‘Sunset in My Hometown,’ directed by ‘Lee Joon-ik.’ The film opened to positive reviews with critics praising the performance of the cast. The following year, she made a cameo appearance in the South Korean action police procedural film ‘Hit-and-Run Squad.’
In 2021, Kim joined the main cast of the psychological drama South Korean television series ‘Yumi's Cells.’ The show completed its first season in October 2021. She will be next seen in the upcoming South Korean television series ‘Little Women’ where she will play the role of ‘Oh In-ju.’ Kim will also be a part of the upcoming film ‘Hero.’