The former president of Malaysian Medical Association (MMA) was known for his passion for social justice, democracy and political freedom. As a young medical student at the University of Malaya which was then based in Singapore, Rajakumar co-founded the Socialist Club of the university and his radical views on western imperialism in Asia led to a sedition suit in court. 

He was also involved in the talks of the Malaya-Singapore debate and eventually became one of the key leaders of the Labour Party of Malaya until its deregistration in 1972. 

Moving his focus back to his medical profession, Rajakumar started advocating for affordable healthcare and spearheaded the local medical association's historic and in-depth review of the Malaysian Healthcare System in 1970s. He was also responsible for setting up the 'Malaysian Physicians for the Prevention of Nuclear War' (MPPNW) within the MMA. 

Often regarded as the father of primary health care, Rajakumar went on to set up the Malaysian Academy of Primary Health Care Physicians. His outstanding contributions to the primary health care sector was recognised by the World Organisation of Family Doctors (WONCA) that established the 'Rajakumar Movement' in 2008 to foster mentoring between current and future leaders in family medicine in the Asia Pacific region and allow them to further explore the depths of family medicine. 

Rajakumar passed away on 22 November 2008 due to heart and lung complications at the age of 76.