Ha Dong-Hoon was born on August 20, 1979 in Berlin, Germany and moved to Seoul, South Korea when he was an infant. His parents are both Korean and he has an older sister, Ha Juri who is a pianist. Ha Dong-Hoon graduated from Daejin University, where got a Masters degree for Drama and Fine Arts. He later became a trainee for Seoul Records debuted as a singer and rapper in 2001 with boy band, Zikiri. Despite excessive promotion, Zikiri failed to get popular and was quickly disbanded.In 2002, Ha Dong-Hoon became a co-host for the show, What's Up YO! alongside MC Mong and Jerome To. The three later became known as the "What's Up Trio" because of their strong friendship on-screen. Ha Dong-Hoon later joined the main cast of the third season of Nonstop, a sitcom about a group of college students and their friends and family. He remained part of the cast up until 2003 which managed to gain him recognition for his acting and comedy skills. Haha later became the producer and presenter for his own radio show with MC Mong, known as HaHa and Mong's Journey in 2004 for SBS Power FM.After leaving Nonstop, Ha Dong-Hoon spent two years alongside singer, Taw, preparing and recording his debut album titled, "The Beautiful Rhyme Diary". The album was released on February 18, 2005 alongside his debut single, "Love Song" but failed to chart or garner much popularity. In December 2005, Ha Dong-Hoon became a member of the game show, Infinite Challenge. He also returned as a guest for the sixth and final season of Nonstop in 2006. In 2007, Ha Dong-Hoon released his second single, "You're My Destiny" which took a samples from the song "Stand By Me" by Ben E. King. The single managed to reach number one on the Gaon Chart and he performed on his Comeback Stage on Music Bank in November. Ha Dong-Hoon later joined the show, Happy Shares Company as a co-host until February 2008.In February 2008, Ha Dong-Hoon temporarily left Infinite Challenge in order to serve his national service for the army. Previous reports had stated that he had been attempting to evade his military service however, these reports were confirmed to be false and Ha Dong-Hoon's service had only been postponed. During his service, he collaborated with a new group Davichi in their song "Love and War". After 24 months of serving the military, on March 11, 2010, he was discharged from the military.After finishing his duty, Ha Dong-Hoon returned to Infinite Challenge. He also made regular guest appearances on Yu Jae-Suk's talk show Come to Play and was the co-host of the Haha-Mong Show with MC Mong up until allegations had sprung up that MC Mong had attempted to evade his military service.Since 2010, Ha Dong-Hoon is one of the permanent cast members for the variety show Running Man, with host-in-chief Yu Jae-Suk. On December 30, 2011, Ha Dong-Hoon received the award for "Best Entertainer" during the 2011 SBS Entertainment Awards for his work on Running Man. He also performed his single, "Rosa" during the award ceremony.