Lee Ha-yool debuted as an actor in the 2011 MBC medical suspense drama Night Hospital. That same year, he appeared in the JTBC fantasy romance Padam Padam. In 2014, he played supporting characters in SBS’s Angel Eyes and MBC’s Records of a Night Watchman. In 2015, he starred alongside Go Won-hee in the KBS2 daily series The Stars Are Shining. In 2016, he joined the main cast of the MBC daily drama Person Who Gives Happiness, which earned him an Excellence Award nomination at the MBC Drama Awards. In 2019, he portrayed a National Intelligence Service agent in tvN’s Designated Survivor: 60 Days, which was based on the U.S. series Designated Survivor. In 2021, he became part of the OCN military thriller Search, which was followed by a supporting role in the 2022 tvN revenge melodrama Eve.

Lee Ha-yool dated his The Stars Are Shining leading lady Go Won-hee for almost three years.