Born on 11 March 1944 at Thana Line in Darjeeling town to mother Krishna Mati and father Bir Hang Subba, Kumar Subba went to the Bhanu Bhakta Primary School in the town, where his teachers included the noted poet Agam Singh Giri. Subba cleared his class-X board exams from Turnbull High School in Darjeeling, and later joined the Harsing Primary School as a teacher in 1964. Fond of singing since his childhood, Subba later joined the Song and Drama Unit in the West Bengal Department of Information and Culture in 1985. Subba made his first major appearance when he sang a song written and composed by Ashok Rai in the Gorkha Dukha Niwarak Sammelan hall in Darjeeling in 1963, and went on to record his first song at the HMV studios in Kolkata in 1968, the year he also started his association with Radio Kurseong and Radio Nepal. Among the several awards and citations he received were the ‘Rajya Abhisekh’ Silver Medal in Nepal (1974), Dishari Puraskar, Kolkata, 1991, Aruna Lama Saalig Nirmaan Puraskar, Bijanbari, 1999, Aruna Lama Smriti Puraskar, 2001, Samman Puraskar, Gorkha Jan Mukti Morcha, Darjeeling, 2006, and the Sangeet Samman Puraskar, West Bengal Government, 2012.