[3] In 2017, Yoo was accepted through rolling admission into the musical theatre program of the Performance & Film Department at Dankook University.

[12][13][14] Yoo collaborated with Brother Su and participated in the soundtrack of Love Playlist 2 with the track "Toy".

[20][21] Yoo released two soundtracks for television series in 2018, "Your Name Is..."[22][23][24] and "Stay With You"[25][26] for The Undateables and Where Stars Land respectively.

[33][34] On May 4, 2021, Yoo and the members of I.O.I celebrated their 5th debut anniversary with a reunion live stream show called "Yes, I Love It!".

[36][37] On August 10, Yoo and Dawon released a cover song of Taeyeon's "Starlight" for NORAE-ing LIVE of Time.

[40][41] Yoo collaborated with MJ of Sunny Side on the track "Guardian Angel", which was released on October 31, 2021.

[44] Later, in July 2022, Yoo joined the stage play Crash Landing on You, an adaptation of the television series.