Sundarrajan's first stint with acting came when he was in the sixth grade; at this point he was cast in a Hindi play of his school.

[2] After graduating with a degree in science, Sundarrajan went to Madras (now Chennai), where his uncle Veeraraghavan was an amateur actor in the Triplicane Fine Arts theatre troupe.

[2] Sundarrajan subsequently received opportunities to act in the plays of K. Balachander, most notably Major Chandrakanth, where he portrayed the title character.

[4] Sundarrajan went on to appear in over 900 films and continued to act in plays, eventually launching his own theatre troupe.

[1][3][5] Sundararajan was well known for his sophisticated and urbane way of delivering dialogues, often mixing English and Tamil sentences.