After modeling in some commercials, Kim became interested in acting. In 2011, he made his acting debut in the psychological thriller White Christmas, and he also had a role in the sitcom Vampire Idol that same year. 

Although Kim Woo Bin had supporting roles in A Gentleman's Dignity and  To the Beautiful You in 2012, it wasn’t until 2013 that he became a breakout star. First he had a lead role alongside Lee Jong Suk in School 2013, and then he played the second male lead in the massive hit Heirs, opposite Lee Min Ho. After gaining popularity in Heirs, he spent 2014 starring in two feature films: Friend 2 and The Technicians. He also made a cameo in the web series Love Cells.