[2] Song made his acting debut with a supporting role in the 2017 romantic comedy television series The Liar and His Lover.

[5][6] On July 8, 2017, his agency Namoo Actors organised a fan meeting – "Introduction to Rookies" for Song alongside Oh Seung-hoon and Lee Yoo-jin.

[11] In 2019, Song played the supporting role of Jung Kyung-ho's assistant in tvN fantasy melodrama When the Devil Calls Your Name.

[16] Song was propelled to stardom in 2020 when he starred in apocalyptic horror Netflix original Sweet Home, based on the eponymous webtoon.

[17] His role was Cha Hyun-su, a suicidal high school boy who, along with a group of fellow apartment residents, tries to survive a "monsterization" apocalypse.

[25] In terms of viewership record, 2021 was considered a success for Song as Sweet Home, Love Alarm, and Nevertheless respectively ranked as fifth, sixth, and eighth most watched K-dramas in Netflix worldwide, respectively.

[31] On February 29, 2024, Namoo Actors announced that Song will enlist to fulfill his mandatory military service as an active duty soldier on April 2.