Lee Gyu-lee is a business writer at The Korea Times, focusing primarily on IT & telecommunications, the Ministry of Trade, Industry and Energy and KOTRA. Prior to this, she has covered a wide range of cultural news, from film, television and K-pop to lifestyle and fashion.
Seo Kang-joon wraps up ‘Undercover High School’ in high spirits

Scenes from the final episode of "Undercover High School" / Courtesy of MBC
By Lee Gyu-lee
Actor shows new side of himself in comeback series
Actor Seo Kang-joon reflected on wrapping MBC’s action comedy series “Undercover High School,” his small screen return after completing mandatory military service, saying he was pleased to show a new side of himself through the character Jung Hae-sung.
"I remember the times spent working together with many staff members while filming this series. From the hot summer through the cold winter, I want to express my gratitude to everyone who gave their all without holding back,” Seo said through the broadcaster.
"(The series) holds meaning in that it showed a new side of me after being discharged from military service. I was happy to meet this 'cool guy' Jung Hae-sung, who is quite different from the characters I've played before and I hope he is remembered in the viewers’ hearts further on. I want to express my thanks to everyone who cherished him."
The 12-part series follows a National Intelligence Service ace field agent, Jung, who goes undercover at a prestigious high school. Disguised as the school’s newly transferred student, he carries out an operation to find King Gojong’s missing gold bars. But the operation takes a turn when he meets his homeroom teacher Oh Soo-ah (played by Jin Ki-joo), who was his childhood friend.
The series concluded Saturday with Jung completing the mission to find the gold bars and putting the school’s chair behind bars. Oh, who helped Jung with the operation, accomplishes her dream of becoming a full-time teacher and finds happiness in her romance with Jung. The final episode garnered a 5.8 percent viewership rating.
Jin also expressed gratitude to the viewers, sharing that the series helped her grow as a person.
“'Undercover High School' is a work that made me become a bit more mature. Through this series, I was able to experience a character with a strong heart to protect someone, and I was able to become more solid as I filmed it,” she said through her agency, FL Ent.
“Thanks to everyone who watched Soo-ah with love … I think I'll be able to let go of Soo-ah without regrets thanks to that love. I hope you had a lot of good laughs through the drama," she said. "Thank you so much for supporting and staying with 'Undercover High School' until the end."