Raja Wanasundera was born in Ratnapura on 11 February 1924 to a Kandyan family.
He was promoted to Solicitor General, succeeding Hector Deheragoda, and held the office until 1974.
[2] With the stepping down of Chief Justice Suppiah Sharvananda, Wanasundera, the senior most judge on the bench, was passed over as his successor when President J. R. Jayewardene appointed Justice Parinda Ranasinghe as his replacement.
Justice Wanasundera had previously given a dissenting judgment against the government.
[6] The Sri Lanka Bar Association deplored this appointment.