Kim Nam-hee began his acting career by appearing in several short films before officially debuting in the 2013 movie A Praise of Youth. He started to gain wider attention in 2018 when he played a Japanese colonel in tvN’s Mr. Sunshine. His performance in the series won him Best Supporting Actor at the 26th Korea Culture and Entertainment Awards. In 2019, he was cast in MBC’s Spring Must Be Coming and in tvN’s Search Query: WWW. In 2021, he became part of the MBC workplace comedy On the Verge of Insanity, which scored him a Best Supporting Actor nomination at the MBC Drama Awards. In 2022, he acted alongside Song Joong-ki and Lee Sung-min in the top-rating JTBC series Reborn Rich. In 2023, he joined the main cast of the tvN spy comedy Family: The Unbreakable Bond.

Kim Nam-hee studied theater and film at Seokyeong University. In September 2018, he married his long-time girlfriend in a private ceremony in Seoul.