Kim Da-mi debuted as an actress in the independent film titled 2017 Project with the Same Name. In 2018, she became part of the crime thriller movie Marionette. That same year, she played the titular character in the mystery horror action film The Witch: Part 1. The Subversion, in which she raked in numerous acting recognitions, including the Best New Actress at the 55th Grand Bell Awards and the Cheval Noir Award for Best Actress at the 22nd Fantasia International Film Festival. In 2020, she acted alongside Park Seo-joon in the hit JTBC series Itaewon Class, in which she received the Best New Actress trophy at the 56th Baeksang Arts Awards.

Kim Da-mi attended Incheon National University’s Department of Performing Arts.