Yeon Jung-hoon made his acting debut in the 1999 SBS drama Wave. In 2003, he starred in the KBS1 daily series Yellow Handkerchief, which won him Best New Actor at the KBS Drama Awards. In 2008, he was cast in the acclaimed MBC drama East of Eden, which scored him the PD Award at the MBC Drama Awards. In 2013, he reunited with his East of Eden co-star Han Ji-hye in the MBC series I Summon You, Gold,  which earned him an Excellence Award at the MBC Drama Awards. In 2015, he was named Best Actor at the 28th Grimae Awards for his performance in the SBS romantic melodrama Mask. In 2018, he took home a Top Excellence Award at the MBC Drama Awards for his work in My Healing Love.

Aside from acting, Yeon Jung-hoon also hosted four seasons of the motoring program Top Gear Korea. In November 2019, he became a fixed cast member of the KBS2 variety show 1 Night 2 Days, in which he was named Best Entertainer at the 2020 KBS Entertainment Awards. He also released an album titled Yeon Jung-hoon Vol. 1 way back in October 2005.

Yeon Jung-hoon and his Yellow Handkerchief co-star Han Ga-in tied the knot on April 26, 2005. They have two children together. He enlisted for his mandatory military service in November 2005 and was discharged in October 2007.