Born in Kanchipuram, son of old actor "Loose Arumugam", Mohan migrated to Madras at an early age and debuted at age 16 in the 1944 filmHarichandra as P. U. Chinnappa's son. However, most of his successes were in the late 1970s and 1980s when he acted as a comedian alongside stars such as Kamal Haasan and Rajinikanth.
Mohan acted in his last film role in 2002. He was forced to quit acting due to his deteriorating health. In 2009, Mohan filed a case against his son Karthik for neglecting his health. He died on 16 September 2012, aged 84, from respiratory problems.