Following the disbandment, Lee embarked on a solo career in South Korea under SM, releasing two digital singles.

In 2009, she debuted as a solo singer in Japan, under Avex's Rhythm Zone, taking the stage name Iconiq, and released a studio album, an EP, and seven digital singles.

Lee simultaneously changed her romanization of her stage name from Ahyoomee to AhYooMi and released her first digital single "Cutie Honey" on July 13, 2006.

[6] The single originally sung by Kumi Koda for the theme song to the Cutie Honey anime series.

[16] On August 11, 2010, she released her debut single "Tokyo Lady", which was later included in her first EP Light Ahead in September.

[18] In August 2016, in an interview with SENSE (ja) magazine, Lee stated she would be going back to being an actress, using the name Yumi Itō.

[20] In August 2017, Lee officially resumed her Korea activities with confirmed as a cast member of MBN's new South Korean variety show Flight Girl.

[22] In September 2022, Lee released a pre-wedding photo revealing that she would marry her non-celebrity foreign boyfriend who is two years older than her on October 30.