In 1946 Wimalasena was elected to the Kandy Municipal Council, serving as Deputy Mayor in 1946 and as Mayor in 1963.
In March 1960 he ran as the UNP candidate for parliament in the Senkadagala Electoral District. He was successful, securing over 48% of the vote.[2] However, as neither of the major political parties managed to obtain a sufficient majority in the election a new election was called. At the July 1960 election Wimalasena lost by a narrow margin of 25 votes to the SLFP candidate, Shelton Ranaraja.[3]
In December 1977 he was appointed as the Sri Lankan High Commissioner to the United Kingdom serving until January 1981. Upon his return to Sri Lanka he was the Deputy Director-General for the Greater Colombo Economics Commission.