K. Kumar was born in Elanthur village in Pathanamthitta district in 1894. He was one of the early freedom fighters in Travancore who brought the message of Gandhiji to the people of Travancore. As a pioneering socio-political leader, he brought the spirit of a national movement to Travancore. He was the president of the Travancore State Congress Committee. He revived the newspaper Swadeshabhimani, which was earlier edited by Ramakrishna Pillai. He spread the message of the national movement in Travancore through this newspaper till 1932.
In 1930 he moved to Malabar to participate in the Salt Satyagraha and other agitations in connection with Civil Disobedience Movement. He attended Salt Satyagraha meetings in Kozhikode, Thalassery, and Kannur. In Travancore, he participated in various agitations of the freedom movement. He boycotted foreign clothes and picketed shops selling foreign goods. He was arrested and imprisoned for two years. He served as a member of the All India Congress Committee and later on Congress Working Committee. He also headed the Constructive Work Committee of KPCC.
He had accompanied Gandhiji on his tours all over Kerala during his visit. He translated the speeches of Gandhiji into Malayalam.
Later he turned his attention to Harijan welfare measures and the promotion of Khadi and Sarvodaya education in Travancore.
He passed away in 1973.