Ivy debuted as a singer in 2005 with the single What Happened Tonight, which won her Rookie of the Year at the 20th Golden Disc Awards. That same year, she released her debut studio album My Sweet and Free Day, which featured 15 tracks. In 2007, she was named Best Female Artist at the Mnet Km Music Festival for the song Sonata of Temptation from her second studio album A Sweet Moment. In 2010, she made her theatrical debut in Kiss Me, Kate. In 2012, she played Roxie Hart in the musical Chicago, which gave her the Best New Actress trophy at the Korea Musical Awards. In 2018, she took home the Best Actress honors at the Yegreen Musical Awards for her performance in Red Book.
In 2007, Ivy got embroiled in a sex tape scandal that forced her to go on a hiatus. In 2012, she appeared in the SBS talk show Strong Heart, where she firmly denied the issue and discussed its negative impact on her and her family. She dated composer Kim Tae-sung, whom she met in 2008 while recording her comeback album I Be… They broke up in 2012 after two years of being together.