Sohn Ho-joon first forayed into acting in the 2006 EBS educational drama Jump 2. The following year, he was launched as the leader of the short-lived South Korean boy group Tachyon. They released a Korean remake of the V6 song Feel Your Breeze as their debut single and then disbanded afterwards. His claim to fame was his role as Haitai in the hit 2013 tvN series Answer Me 1994, which won him Best New Actor at the 3rd APAN Star Awards. In 2015, he bagged the New Star Award at the SBS Drama Awards for the police procedural series Mrs. Cop. In 2016, he acted alongside Im Ji-yeon in the MBC weekend drama Blow Breeze, which earned him an Excellence Award at the MBC Drama Awards. In 2017, he was paired with Jang Nara in the KBS2 series Go Back Spouses, which scored them the Best Couple Award at the KBS Drama Awards. In 2019, he landed a major role in JTBC’s The Light in Your Eyes, in which he was nominated for Best Supporting Actor for TV at the 55th Baeksang Arts Awards.

Sohn Ho-joon enlisted for his two-year mandatory military service in 2010. He is close friends with TVXQ’s U-Know Yunho and his Answer Me 1994 co-star Yoo Yeon-seok.