Ji Hyun-woo debuted as the lead guitarist for the South Korean rock band The Nuts in 2001 before jumping into acting in 2003. His early notable works include the 2004 KBS2 sitcom Old Miss Diary and the 2005 KBS2 series Golden Apple, with the latter winning him Best New Actor at the 2006 KBS Drama Awards. In 2008, he starred in the SBS romantic drama My Sweet Seoul along with Lee Seon-kyun and Choi Kang-hee. His work in the series earned him the New Star Award at the SBS Drama Awards. In 2011, he received an Excellence Award at the MBC Drama Awards for the weekend series A Thousand Kisses. Also in 2011, he dropped his first solo mini-album called Crescendo. In 2012, he starred in the hit tvN drama Queen In-hyun’s Man, opposite Yoo Inna. In 2021, he led KBS2’s Young Lady and Gentleman, which gave him the Daesang at the KBS Drama Awards.

Ji Hyun-woo’s older brother Ji Hyun-soo is also a musician, who was part of the South Korean rock band N.EX.T. In June 2012, it was confirmed that Ji Hyun-woo and his Queen In-hyun’s Man leading lady Yoo Inna were dating. The confirmation came after the actor publicly declared his love for the actress during a fan meeting for the TV series. Ji Hyun-woo enlisted for his mandatory military service in August 2012. He was discharged in May 2014. That same month, news about his breakup with Yoo Inna came out.