In 2018, she appeared as a contestant on the survival show Produce 48 where she represented Pledis Entertainment. She was eliminated in episode 11 after ranking 26th place.
Following the conclusion of Produce 48, it was rumored that she and fellow label mate and contestant Kaeun would debut in a new girl group together. But, after Kaeun left Pledis Entertainment, plans for the group's debut fell through.
2021–2022: Source Music, debut with LE SSERAFIM
On August 24, 2021, it was revealed that Yunjin had officially signed a contract Source Music and would be debuting as a member of the agency's new girl group, LE SSERAFIM, in May.
On April 9, 2022, she was introduced as the sixth and final member of LE SSERAFIM. They debuted on May 2, 2022 with the mini album Fearless.
On March 4, 2019 Yunjin became a student of the Applied Music Department at Hanlim Multi Art School. Apparently, she didn't finish her graduation.
Producing and writing credits
Credits taken from the official track list teaser for Fearless.