So Ji Sub's Agent Kim Reactivated smashes 5-year ratings record; everything to know about 2026's biggest K-drama hit

AGand Kim Reactivated is proving to be the breakout Korean dramatic event of the twelvemonth. The SBS and Netflix serial publication made a powerful take up with the highest premiere ratings for a miniseries in 2026, and instead of slowing down, it attracted even more viewers with its second episode. Starring So Ji Sub in the lead, the revenge thriller has already achieved a milestone that few dramas manage today. Just two episodes into its run, it has emerged as one of 2026's biggest K-drama hits, with viewers showing up in huge numbers week after week.Agent Kim Reactivated reaches a major ratings milestoneAccording to Nielsen Korea report, the second episode of Agent Kim Reactivated, which aired on June 27, pulled in an average nationwide rating of 15.7 percent. With this, the SBS drama not only became the network’s top-performing series of 2026 so far, but also became the fastest show in five years to pass the 15 percent mark, a milestone last reached by The Penthouse 3 in 2021.The show also performed strongly with younger viewers, recording an average rating of 5.8 percent in the 20–49 age bracket. At a time when audiences are increasingly divided between streaming platforms and traditional TV, the drama has still managed to pull viewers back to live broadcasts in large numbers.On the same night, competition struggled to keep pace. Another network MBC’s Fifties Professionals signed off with 5.0 percent, JTBC’s Reborn Rookie hit a personal best of 10.4 percent, and KBS 2TV’s Recipe for Love delivered a steady 14.4 percent. While all three had decent runs, none came close to challenging the dominance of Agent Kim Reactivated, which clearly led the ratings chart for the night. Who is Seo Ji Sub?So Ji Sub has built a career that moves easily between emotional dramas, romance, and action. He became a household name with Sorry, I Love You (2004), where his intense and heartbreaking performance left a lasting impact on Korean television. He also been seen in Cain and Abel (2009) and Always (2011). Over the years, he showed his lighter and romantic side in popular hits like The Master’s Sun (2013) and Oh My Venus (2015), while also proving his strength in films such as A Company Man (2012) and The Battleship Island (2017).In 2026, he has returned to TV with Agent Kim Reactivated. Playing a damaged NIS agent pulled back into danger, he delivers a performance full of emotion and intensity.What is Agent Kim Reactivated about?Agent Kim Reactivated tells the story of Kim Seok Joo (So Ji Sub), a former National Intelligence Service operative who left the job behind after a mission left him emotionally shaken. He has since been living in silence and isolation, far from his old life. But everything changes when a new danger surfaces, pulling him back into the field he thought he had escaped forever.The drama combines fast-paced action with a deeply personal revenge story. As missions unfold, the series also shows his emotional struggle, as he is pushed to face old wounds while chasing justice.The cast also includes Kim Ha Neul plays Seo Yoon Ji as someone deeply tied to his past, Lee Joon Hyuk portrays the role of Cha Min Ho as a powerful rival with personal stakes. Jang Hyuk plays Kang Tae Sik, a seasoned agent who remains active in the field and shares a complicated dynamic with the lead. Lee Young Ae takes on the role of Director Hwang, the NIS chief whose shifting loyalties keep everyone guessing.Creators behind the showDirected by Lee Yoon Jung, known for The Veil and Vagabond, the series carries her signature tone; realistic action sequences mixed with strong emotional undercurrents. The writing is handled by Jang Young-chul and Jung Kyung-soon, the team behind The Penthouse and The Vengeance Trilogy.