Manmohan completed his pupillage with Mr P S Ranjan and was admitted as an advocate and solicitor of the High Court of Malaya on 17 August 1990. Since then he has practised in P S Ranjan & Co and was admitted as a partner in 1997 and is currently the senior partner.

He is a member of the Medico-Legal Society of Singapore.

He has been a legal adviser to patients support groups, medical organisations, hospitals and other healthcare personnel and organisations. He has also been invited to speak at various medico-legal conferences, seminars and meetings and has attended medico-legal seminars and conferences held in various parts of the world.

He has appeared as counsel for claimants, doctors and hospitals in all tiers of our courts and has also appeared as counsel before the Malaysian Medical Council and the Malaysian Dental Council on behalf of both complainants and doctors. He has also appeared as counsel for doctors who had faced criminal proceedings in court. He has in the past also been involved as counsel in some matrimonial, defamation, employment , commercial and corporate cases. He has conducted and assisted in domestic inquiries in cases involving both the medical and legal professions. Apart from appearing as counsel in various medico-legal proceedings involving doctors, hospitals, patients and their next of kin, he is also actively involved in giving legal advice and assistance on medico-legal issues to the various stakeholders in the healthcare industry and to his brethren in the legal profession.

Manmohan and his colleagues in Messrs P S Ranjan & Co have appeared as counsel in many of the reported medico-legal cases. The medico-legal team in Messrs P S Ranjan & Co work closely with their visiting medical advisers in assessing medico-legal cases with a view to advising clients on liability, standard of care,  foreseeability, causation, prognosis and causation.

He has an interest in community and charity work and tries to exercise as often as possible.