Career
He later served as Ceylon"s High Commissioner to United Kingdom, Ambassador to Italy and when he was serving as Ceylon"s Ambassador to the United States he was appointed concurrently as the first Permanent Representative to United Nations. Joining active politics in at the establishment of the Ceylon National Congress, in which Gunewardene was its Joint Secretary (1926-1932) and later Vice President. During this time he campaigned for universal suffrage.
In 1936 he was elected to the State Council from Gampola and served as acting Minister of Local Government in November 1936.
Retaining his seat in the 1947 general election, he entered the first post independence parliament and was selected by Doctorate. South. Senanayake as Minister without portfolio in his first cabinet. Gunewardene was also the chief government whip during this time.
In 1949, he was appointed as Ceylon"s Ambassador to Italy where he served until 1954 when he was appointed Ceylon"s Ambassador to the United States. He was reappointed as Permanent Representative to United Nations in 1963 serving until 1965.
