Kim Min-seok joined Mnet’s Superstar K3 in 2011 but was eliminated early in the competition. In 2012, he made his acting debut as one of the main characters in the tvN series Shut Up: Flower Boy Band. He then played supporting roles in the KBS2 dramas High School: Love On and Who Are You—School 2015, which aired in 2014 and 2015, respectively. His career breakthrough came in 2016 when he became part of the widely popular KBS2 drama Descended From the Sun, which earned him several Best New Actor nominations. He next appeared in the SBS series Doctors, which won him the New Star Award at the SBS Drama Awards. He was also named Best New Actor at the 53rd Baeksang Arts Awards for his work in the series. In 2017, he joined the cast of the SBS legal drama Defendant, which scored him an Excellence Award nomination at the SBS Drama Awards. That same year, he landed key roles in JTBC’s Age of Youth 2 and tvN’s Because This Life Is Our First.

Kim Min-seok enlisted for his mandatory military service in December 2018 and was discharged in July 2020.