Karunanidhi entered politics at the age of 14, inspired by a speech by Alagiriswamii of the Justice Party, and participated in Anti-Hindi agitations. He founded an organisation for the local youth of his locality. He circulated a handwritten newspaper called Manavar Nesan to its members. Later he founded a student organisation called Tamil Nadu Tamil Manavar Mandram, which was the first student wing of the Dravidan Movement. Karunanidhi involved himself and the student community in social work with other members. Here he started a newspaper for its members, which grew into Murasoli, the DMK party's official newspaper.
The first major protest that aided Karunanidhi in gaining ground in Tamil politics was his involvement in the Kallakudi agitation in Kallakudi. Original name of this industrial town was Kallakudi and it was changed to Dalmiapuram after a cement mogul from North India who built a cement plant there. DMK wanted to change the name back to Kallagudi.. In the protest Karunanidhi and his companions erased the name Dalmiapuram from the railway station and lay down on the tracks blocking the course of trains. Two people died in the protest and Karunanidhi was arrested.