Chandrappan, who had come into politics as a student activist in 1950s, took the reins from Veliyam Bhargavan in 2011.
Chandrappan had served as national president and general secretary of the All India Students Federation (AISF) and president and general secretary of the All India Youth Federation (AISF). He was elected to the Lok Sabha from Thalassery (now Kannur) and Thrissur and to the state Assembly once from his hometown, Cherthala.