During his Diploma in Technical College in 1970, he joined the JVP full time. During the 1971 JVP insurrection, Gunaratne worked as the organizer of the Puttalam District. Before the insurrection, he conducted JVP classes in the jungles on the banks of the Deduru Oya. On April 5, 1971, a group of about 25 people, including Senaratne Silva, Wanasinghe led an attack to the Chilaw police. Then he was arrest for organizing riots and released in mid 1970s. Then he became the principal of a small school and temporarily quit from politics.