 He joined the Jathika Hela Urumaya (JHU) political party along with members of the Sihala Urumaya as the Propaganda Secretary, when it was formed in 2004 to wheeled candidates who were all Buddhist monks, for Parliament in the 2004 general election.Gammanpila was later appointed as the Administrative Secretary of the party  and he presently functions as the Party’s Legal Advisor.He played a major role on behalf of his party supporting Mahinda Rajapakse's presidential election campaign in 2005.