Shim Eun-jin launched her singing career in 1998 as a member of Baby V.O.X, one of the most prominent South Korean girl groups of the 1990s. She was the first to leave the group at the end of 2004, publicly stating that she did not agree with the direction their record company DR Music was heading.

After a short absence from the entertainment scene, Shim re-emerged at the end of 2005 with her first solo album, Zeeny’s, which was released by the label CJ Music on December 16, 2005. The first single, “Oopsy,” was a sexy dance number, allowing Shim to showcase her sexy dance moves (which she was best known for during her time as a Baby V.O.X member). She then moved on to a ballad as her second single, although it was not promoted heavily, sales of the album were a mediocre. While promoting her album, Shim went on various variety shows, and launched her clothing line, Z’BAGO.

In 2006, Shim made her acting debut in the period drama Dae Jo-yeong.

She held her first solo art exhibition titled Share Joy and Sorrow at the Jeong-am Art Gallery in June 2013; more than 60 of her artworks were on display, including photographs, croquis. and writings.