G.R.Kamat, known as Gajanan Ramchandra Kamat, was born in a poor farmer family in Chira village, Kolaba district of Maharashtra. His mother's name was Seetabai, and she died when G.R.Kamat was two years old. He studied at the local Alibag school till class seven. After that, he moved to Bombay. G.R.Kamat joined the Ramnarain Ruia College, where he got influenced by his professors, namely N R Phatak and Sonopant Dandekar. Additionally, he had friendships with writers M V Rajadhyaksha, P Bhagwat, and Ram Patwardhan. Bhagawat gave him the position of assistant editor for "Mauj" and "Satyakatha," two of the most well-known literary periodicals at the time, in 1945. Additionally, Kamat worked for a short while for the daily newspaper Navakal.
Although he intermittently worked on a few Marathi films, he decided to focus on Hindi films in 1966. He had a successful career as a screenwriter in Hindi cinema, penning the scripts for movies like Kala Pani (1958), Bombai Ka Babu (1960), Do Badan (1966), Do Raaste (1969), Mera Gaon Mera Desh (1971), Do Chor (1972), Kuchhe Dhaage (1973), Main Tulsi Tere Aangan ki (1978), Do Pre With Kala Pani (1958). Kamat had started writing scripts with
, and they continued to work together on all of his movies until the early 1980s. After the Hindi films "Teri Mang Sitaron Se Bhar Doon" and "
" in 1982, he announced his retirement. However, newer directors like "Jyotin Geol" continued to seek his advice.