Yoo Yeon-seok (유연석), whose real name is Ahn Yeon-seok (안연석), is a South Korean actor born on April 11, 1984, in Seoul. A graduate of Sejong University with a degree in film arts, he made his film debut in 2003 in Oldboy by Park Chan-wook, in which he plays the younger version of Lee Woo-jin. After completing his military service, he truly resumed his acting career in 2008 and adopted the stage name Yoo Yeon-seok.
During his early years, he took on numerous supporting roles in film and television. He notably made a name for himself in Re-encounter, and then plays antagonist roles in hit films Architecture 101 and A Werewolf Boy. Its popularity grew significantly in 2013 thanks to Chilbong in Reply 1994, a role that marked one of the first major turning points in his career.
He then reaffirmed his status as a leading figure with Warm and Cozy in 2015, and especially with the medical drama Dr. Romantic in 2016, in which he plays the surgeon Kang Dong-joo. In 2018, he played the standout role of Goo Dong-mae in Mr. Sunshine.
Between 2020 and 2021, Yoo Yeon-seok enjoyed another major success with Hospital Playlist and its second season. In it, he plays Ahn Jeong-won, also known as Andrea, an assistant professor of pediatric surgery and a member of the group of friends at the heart of the series. He continues with Narco-Saints and The Appeal of Love in 2022, and then played the criminal Geum Hyuk-soo in the thriller A Bloody Lucky Day in 2023. That same year, he also reprised his role as Kang Dong-joo in the third season of Dr. Romantic.
In 2024, he returned to a leading role in When the Phone Rings, in which he plays Paik Sa-eon. For this series, he received the Top Excellence Award at the MBC Drama Awards and shared the Best Couple Award with Chae Soo-bin. In 2025, he briefly reprised his role as Ahn Jeong-won in Resident Playbook and makes a special appearance in Tastefully Yours.
In 2026, he played the lead role of Shin Yi-rang in The Phantom Lawyer (Phantom Lawyer) and Min Jun-ho's in The Perfect Lie (Liar). It is also featured in the historical drama Covet the Scholar, Princess, in which he is set to play Kim Seo-yul.
In addition to his work in front of the camera, Yoo Yeon-seok has had a successful career on stage, particularly in musicals Hedwig and the Angry Inch, Werther and A Gentleman’s Guide to Love and Murder. In March 2026, he was also appointed professor at Sejong University, his former university, where he teaches a multimedia performance course to theater students.
