Lee Jung-ha first pursued his dream of becoming an idol by joining the KBS2 survival reality show The Unit: Idol Rebooting Project in 2017. He placed 19th among the male contestants at the end of the show. That same year, he made his acting debut in the web series Heart Attack Warning. He then took on minor roles in several television and web dramas, including MBC’s Rookie Historian Gu Hae-ryung and JTBC’s Run On and Nevertheless.


In 2023, Lee Jung-ha joined the ensemble cast of Moving, a live-action adaptation of the popular webtoon by Kangfull. His performance in the series launched him into fame and earned him numerous Best New Actor trophies, including one from the 60th Baeksang Arts Awards. Later that year, he appeared in director Kim Hye-young’s feature debut It’s Okay!, which premiered at the 28th Busan International Film Festival. In 2024, he acted alongside seasoned actor Shin Ha-kyun in the tvN investigative office drama The Auditors.