Jo Byung-kyu made his acting debut in the KBS2 series Who Are You–School 2015. He then had appearances in MBC’s Money Flower in 2017 and in KBS2’s Radio Romance in 2018. He saw a rise in his popularity when he joined the hit 2018 JTBC satirical comedy drama SKY Castle. In 2019, he became part of tvN’s historical fantasy series Arthdal Chronicles. That same year, he was cast in the SBS sports drama Stove League, which was named Best Drama at the 56th Baeksang Arts Awards. He also won Best New Actor at the SBS Drama Awards for his work in the series. In 2020, he starred in the high-rating OCN fantasy-action drama The Uncanny Counter.

Jo Byung-kyu got embroiled in a school bullying scandal in early 2021, but police investigations found that the allegations were fabricated. He previously dated his SKY Castle co-star Kim Bora.