In October of 2017, Ryujin became a contestant on the survival show MIXNINE. She ranked 1st place in the finale, however, was eliminated when the boys' team won against the girls', thus ultimately not being able to debut.
2019: Debut with ITZY
On January 20, 2019, she was revealed as a member of ITZY, JYP Entertainment's newest girl group. The group debuted on February 12, 2019, with the digital single, "IT'z Different".
She, alongside fellow member Chaeryeong, graduated from Hanlim Multi Arts School on February 7, 2020.