In 1954, he joined "The Straits Times" as a journalist. He was bold in writing about the way Singapore was governed by the British. This incurred the displeasure of the colonial government. His column, "I write as I please", attracted so much attention that he was called for questioning by the government. In 1954, Rajaratnam co-founded the People's Action Party together with Lee Kuan Yew, Toh Chin Chye, Goh Keng Swee and others. He became popular among his supporters for being able to effectively follow the 'mood of the people'. He thought of a multiracial Singapore and envisioned her to be a 'global city'. He was also actively involved in organising major political campaigns against Singaporean groups on the far left. During his years in parliament, he served as Minister for Culture (1959), Minister for Foreign Affairs (1965–1980), Minister for Labour (1968–1971), Deputy Prime Minister (1980–1985) and was later appointed as Senior Minister until his retirement in 1988. Rajaratnam is remembered for writing the Singapore National Pledge in 1966. Rajaratnam was Singapore's first foreign minister, following its abrupt independence in 1965. During his tenure as foreign minister, Rajaratnam helped Singapore gain entry into the United Nations and later the Non-Aligned Movement in 1970. He built up the Foreign Service and helped to establish diplomatic links with other countries and secure international recognition of the new nation's sovereignty. He carried out the foreign policy of international self-assertion to establish Singapore's independence during the period when the country faced significant challenges including the Konfrontasi conflict in the 1960s and the withdrawal of British troops in the early 1970s. Rajaratnam was one of the five "founding fathers" of ASEAN in 1967. In this diplomatic arena together with UN he helped to draw international attention to Vietnam's invasion of Cambodia in 1978. Sompong Sucharitkul, an aide of Thailand's then foreign minister Thanat Khoman, conveys Rajaratnam's stance on ASEAN membership for Sri Lanka in 1967:  I remember one was an economics minister. He waited there anxiously for a signal to join the discussion; but it never came. It was Rajaratnam of Singapore who opposed the inclusion of Sri Lanka. He argued the country's domestic situation was unstable and there would be trouble. Not good for a new organisation. During his term as Minister of Labour, he implemented tough labour laws to attempt to restore stability in the Singaporean economy and attracted multinational corporations to invest in Singapore.