He started his political career from the
Sri Lanka Communist Party, of which he was an active member for a few decades. He got remanded for many years trying to topple the government under terrorism act during 1980s. In mid 1980s he and majority of its members left the Communist Party and Socialist People's Movement (සමාජවාදි ජනතා ව්යාපාරය
Samajawadi Janatha Wyapraya) was formed. During the later stages he devoted his time to helping and was actively engaged forming the yahapalana government with
Janatha Vimukthi Peramuna. Soon after De Silva's death, his wife, Sunila Nandani Dias donated de Silva’s library to JVP. De Silva was an active committee member of the Sri Lanka Committee for Solidarity with Palestine, and the Journalists for Global Justice organization. ==Journalism career==