Jinyoung was discovered through the South Korean social network service Cyworld. In April 2011, he was introduced as the leader of the South Korean boy group B1A4. The group released their debut extended play Let’s Fly on April 21, 2011 while their first studio album titled Ignition was released on March 14, 2012. In June 2012, they released their first Japanese single Beautiful Target, which debuted at number 4 on the Oricon weekly singles chart. Aside from leading B1A4, Jinyoung also composed songs for the group. In 2018, Jinyoung and his fellow B1A4 member Baro opted not to renew their contracts with their label WM Entertainment.

Jinyoung made his acting debut in the 2013 tvN drama She Is Wow. He was then cast in the 2014 movie Miss Granny, which became a huge box-office hit. His performance in the movie earned him acting nominations at the 16th Seoul International Youth Film Festival and the 10th Max Movie Awards. His acting breakthrough came in 2016 when he became part of the main cast of the hit KBS2 sageuk Moonlight Draw by Clouds. He won Best New Actor at the 30th KBS Drama Awards and also scored a Best New Actor nomination at the 53rd Baeksang Arts Awards for his work in the drama. In 2017, Jinyoung landed his first film lead role in the body-swap comedy movie The Dude in Me.

Jinyoung enlisted for his mandatory military service in June 2019. He was discharged on April 9, 2021.