She started her career as child actress in 1992 at her age 11 years old, and appeared on a lot of TV dramas like The King's Path (1998, MBC), Spread Your Dreams (1999, EBS), School 3 (2000, KBS), Delightful Girl Choon-Hyang (2005, KBS), etc. In 2007 she appeared on KBS drama Insoon Is Pretty as Insoon's rival in love, Han Jae-eun. In 2009, it was revealed that In-hye became an adjunct professor of the Broadcasting and Entertainment department at Korean Broadcasting & Art School. In 2010, her study tip book, 이인혜의 꿈이 무엇이든 공부가 기본이다, topped the bestseller list that she learned as a top student in school. In 2011, In-hye appeared in the KBS historical drama Gwanggaeto, The Great Conqueror as Yak-yeon, stepdaughter of Ko Mu and later Queen of Goguryeo. In 2012, she appeared in the KBS drama special Disappearance of a Congressman and E-channel sitcom Firm Family. In 2013, She became a full-time professor of Seoul Arts College, and took on dual roles in the KBS drama special Mother's Island as a mysterious woman and ghost. In 2014, she appeared on the TV Chosun period drama Into the Flames.
In June 2017, Lee signed with new management agency Fly Up Entertainment.
