Dongha began his acting career in the 2009 KBS2 romantic comedy series The Accidental Couple. He then made his big screen debut in the 2010 film Hero. In 2017, he was nominated for Best Supporting Actor at the KBS Drama Awards for the workplace drama Chief Kim and for an episode of KBS Drama Special. Also in 2017, Dongha was included in the cast of the SBS legal drama Suspicious Partner, where he played the role of a serial killer. He then starred in the SBS legal series Nothing to Lose, in which he was nominated for an Excellence Award and Best New Actor at the 2017 SBS Drama Awards.

Dongha enlisted for his mandatory military service on May 1, 2018 through the 5th Infantry Division recruit training center in Gyeonggi-do. He served as an active-duty soldier.

In 2020, he made an acting comeback in the hit KBS2 family drama Homemade Love Story.