Hong Soo-hyun began her career as a magazine model while she was still in high school. She made her acting debut in the 1999 SBS drama KAIST. In 2003, she won the Best Supporting Actress trophy at the KBS Drama Awards for her work in Sang-doo! Let’s Go to School! In 2006, she became part of the hit KBS1 sageuk drama Dae Jo-yeong. Originally slated for 100 episodes, the drama was extended for 34 more episodes due to its popularity. In 2011, she won an Excellence Award as well as the Best Couple Award with Lee Min-woo at the KBS Drama Awards for the sageuk The Princess’s Man. In 2013, she took on the MBC weekend family series Will You Love and Give It Away, in which she won an Excellence Award at the MBC Drama Awards.

In 2018, Hong Soo-hyun dated rapper Microdot, whom she met while filming a fishing variety show. They broke up in January 2019. In May 2021, Hong Soo-hyun married her non-celebrity fiancé in a private ceremony.