Sung has also made a name for herself as an actress, first appearing in the miniseries "Bad Girls". Although it was not very successful, she followed it up with the popular series "Thousand Years Of Love" in which she portrayed both a current woman and an ancient princess. The popularity of the drama helped her to win an award for her work as a "Best New Actress". In addition to her dramatic work, she has also co-hosted an entertainment show in 2004 and has been a catalogue model for various companies. Although she briefly returned to music for the Fin.K.L digital single in late 2005, she has returned to acting. In 2006 she played the lead role in two dramas, One Fine Day and Snow Queen in which she won high praises and awards for.
Sung, like all of her Fin.K.L group members, has left DSPent; she is now with SidusHQ, the same company representing actress Song Hye Gyo, suggesting a choice of a permanent acting career.
The daughter of a Christian pastor, she last attended Kyung Hee University.