Dhamayanthi was born in Tirunelveli, in the Indian state of Tamil Nadu. Her parents were teachers, and she imbibed her love for reading and arts from them. She claims that the books her father would gift during her birthday and the inevitable loneliness of childhood made her develop immense interest in books, which later enabled her to develop her passion for writing.
She did her B.A. in English from Sarah Tucker College, Tirunelveli, and her M.A. in English from St. John's, Tirunelveli. Her first couple of were published around this time and she won cash prizes for both. Her subsequent short stories garnered attention and an anthology soon came out. She continued writing poetry, though her fiction was generating more attention and interest. She worked as a radio jockey and program produce in Tirunelveli before moving to Chennai to work as a writer in the film industry.