Ju Ji Hoon is a South Korean actor. His first leading role was as in 2006 television series "Princess Hours". Ju debuted as a model, in advertisements for clothing brands such as Calvin Klein, Levi's and Reebok. Ju's debut drama was "Old Love", but it was in 2006's "Princess Hours", that he was recognized as an actor, for which he won Best New Actor at the MBC Drama Awards.
On April 27, 2009, Ju was arrested by Seoul Metropolitan Police on drug charges. He was arrested along with 15 people and an actress identified as Yoon on suspicion of supplying ecstasy. On June 23, 2009, Ju pleaded guilty in court to drug use of ecstasy and ketamine. He was sentenced to six months of jail time, suspended for one year, 120 hours of community service, and a fine of ₩360,000.
On February 2, 2010, Ju enlisted in the Republic of Korea Army to serve his mandatory military service. Ju was discharged on November 21, 2011.
On May 9, 2014, both Joo Ji Hoon's and singer Ga In's agency both confirmed that they are dating. On July 7, 2017 they have broken up.