Kim Jeong-hoon (born January 20, 1980), also known in Japan as "John Hoon", is a South Korean singer and actor. He initially rose to fame as a member of Korean duo UN debuting with the single Voice Mail in 2000. After the duo disbanded in 2005, his fame increased as an actor starring in Princess Hours, a drama based on a manhwa (South Korean version of a manga).
He debuted as a member of Korean duo UN in 2000, an acronym for "United N-generation". After six years of success, the duo officially announced that they were disbanding in September 2005, and Hoon announced that he was going to pursue an acting career instead. Hoon had stated that the conditions of the Korean music industry prevented him from pursuing music he truly wanted to do.
He originally wanted to be a laboratory researcher. Hoon did not realize that he would become an actor and singer. By 2005 he had already begun starring in Korean dramas, such as sitcom Orange and 남과 여 (A Man and a Woman) in 2004. However Kim Jeong Hoon made his major break through when he starred in the hit MBC drama Princess Hours (Goong) alongside Yoon Eun Hye and Ju Ji-hoon. Jeong Hoon played the role of "Yul" a caring and gentle 19 years old who is second in line to become the crown prince and has returned to Korea to reclaim the two things that were snatched from him after his father's death: The title of crown prince and the crown princess "Chae kyung" who was initially supposed to marry him. He had said his final dream is to become a renowned movie director. On April 28, 2009, he left the public for mandatory military service of two years. 80000 of Kim Jeong-hoon's fans from Japan, Korea, Turkey and China gathered to see him off to serve the country.
After serving two years in military, Kim Jung Hoon returned to civilian life on February 28, 2011. Kim Jung Hoon has appeared in a number of dramas and shows upon his return. He has been cast in an upcoming Chinese drama called “God of War Zhao Yun” (working title) along with Girls’ Generation‘s YoonA. Kim Jung Hoon will portray Li Zhi, a love interest of YoonA’s character in a love triangle. This will be Kim Jung Hoon’s first historical drama.
Kim attended Seoul National University, He took up Dentistry but decided to dropped out to focus on his acting career. But later on he enrolled in Chung-Ang University, where he majors was acting. He was also academically gifted with an IQ of 146.