Mr.Gunasinha's political career marked the formation of the Ceylon Labour Party in October 1928, with himself as President, and Proctor Marshall Perera as Secretary, and Messrs. C.E. Corea, C.H.Z.
At the State Council elections held in 1931 Gunasinha was elected on the Labour Party ticket as Member for Colombo Central Electoral District, and he repeated this feat in 1936.