Kusuma received her education at Ananda Sastralaya and Anula Vidyalaya before entered the University of Colombo.
On 24 August 1950 she married Konara Mudiyanselage Podiappuhamy Rajaratne, a teacher and lecturer, whom she had known since her school days at Ananda Sastralaya.
[8] At the 4th parliamentary election in March 1960 she stood down from representing Welidama allowing her husband to re-contest the seat.
Kusuma however ran in the newly created adjoining seat of Uva Paranagama, as the National Liberation Front (Jathika Vimukthi Peramuna) candidate, which she won, receiving 4,662 votes (40% of the total votes).
[11][12] Kusama was appointed as the Parliamentary Secretary for the Minister of Home Affairs in the Third Dudley Senanayake cabinet but resigned the post in 1966 in protest against the Government's decision to introduce new laws to facilitate the official use of Tamil in administration.