Ji-yeon was born in Seoul, South Korea on June 7, 1993, from a Korean family. She briefly attended Seoul Arts High School and Hyehwa Girls' High School. Eventually, she "gave up a normal high school life" although "misses being a high school girl sometimes" and forsook attending university due to her busy acting schedule and career.



She and Eunjung are the only two members of T-ara to be trained in acting. Instead, the two switched over to singing despite their original intentions. 



Ji-yeon has expressed an interest in modeling. In 2008, when she was 15 years old, Ji-yeon was featured in several pictorials and advertisements for SMART with Korean boy band SHINee. She collaborated with Davichi and SeeYa on the digital single "Female Generation/Forever Love", which was released in May 2009, making her the first member of T-ara to appear in public. She appeared in SG Wannabe's music videos "Saranghae" and "My Love is Crying" from their 2009 album, Gift From SG WANNABE. Early on, the Korean media dubbed Ji-yeon "Little Kim Tae Hee" due to her close resemblance to Kim.



In 2008, she entered and won the Smart Model Contest. Subsequently, she auditioned at the Mnet Casting System and joined the company. T-ara debuted on July 29, 2009, when Ji-yeon was 16 years old; the majority of the members were in their early twenties. She was the youngest member until new member Hwayoung was introduced in 2010. Later, as Hwayoung left T-ara, new member Dani, who was introduced in May 2012, will be dubbed as the new maknae.



Ji-yeon made an appearance on the highly-ranked KBS television show Master of Study as Na Hyun Jung, a heavily burdened love-struck high school girl who joins a special class consisting of five underperforming students who must gain acceptance to the top South Korean university, commonly referred to as the "Cheonha-Dae" (in Korean). Ji-yeon played the lead character in Death Bell 2: Bloody Camp alongside with Yoon Si Yoon, which was released in July 2010. In August 2010, she appeared on HahaMong Show and discussed meeting Park Ji-sung.



During the August 19, 2011 rehearsal taping of KBS Music Bank for their final stage performance of promoting Roly Poly, Ji-yeon pulled a right knee ligament and was rushed to the hospital for further treatment. Her agency released a statement saying that Jiyeon's condition was being monitored. She was reported recovering and continuing to attend tour after tour, although she needed considerable assistance for each trip due to her injuries. Ji-yeon was cast in a drama Dream High Season 2 as Rian/Lee Ji Kyung.



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