Han Sun-hwa made her television debut in SBS’ Superstar Survival in 2004, where she finished as a finalist. In October 2009, she debuted in the four-member South Korean girl group Secret with the single I Want You Back. In 2010, they released their first mini album titled Secret Time, which produced their breakthrough song Magic. The group released a total of two studio albums and six mini albums together.

Han Sun-hwa became a regular cast of the KBS2 variety show Invincible Youth on the same month she debuted with Secret. She then made her acting debut in the 2010 MBC sitcom More Charming by the Day. In 2014, she was cast in the tvN drama Marriage Not Dating, in which she was nominated for Best Young Actress at the 16th Seoul International Youth Film Festival. That same year, she landed her first leading role in the weekend drama Rosy Lovers, which earned her the Best New Actress trophy at the MBC Drama Awards. She also scored a Best New Actress for TV nomination at the 51st Baeksang Arts Awards for her performance in the series. In 2017, she won an Excellence Award at the MBC Drama Awards for her work in the workplace romantic comedy Radiant Office.

Han Sun-hwa’s younger brother Han Seung-woo is a member of the South Korean boy group Victon. As a young girl, Han Sun-hwa showed interest in art and once wanted to become an artist. However, she realized that her dream was to become an entertainer after seeing one of BoA’s performances on TV.