Malcolm Edwards was a product of the manse, being the fourth son of the Reverend John Edwards, minister of St Andrew's Presbyterian Church, Rose Bay and Moderator for the Church in New South Wales. He was educated at the Scots College, Bellevue Hill until 1926, being dux of the school in his last year. He obtained a university exhibition at the Leaving Certificate examination and graduated in medicine in 1933. He was a solid student but did not obtain honours at graduation. He gained a blue for rifle shooting.

After graduating he was appointed a resident medical officer at the Royal North Shore Hospital for two years, following which he spent a year at the Royal Alexandra Hospital for Children. He travelled to England as a ship's surgeon in 1937. During the voyage a passenger was Lorimer Dods who persuaded him to lean towards the study of diseases of children in his postgraduate period. Accordingly he spent a year at the Grosvenor Sanatorium at Ashford, Kent and then two years at Queen Mary's Hospital for Children, Carshalton, Surrey.

After the outbreak of the Second World War he returned to Australia as soon as possible in order to enlist in the Army. After acceptance he was kept on home service for a while and was posted to a prisoner of war camp. He was sent to the Middle East in 1941 and was mainly engaged in hospital work until most of the Australian force was returned to Australia in 1942. He remained on hospital service in Australia until posted to New Guinea in 1944. There again he was involved in hospital work, being promoted to major and mentioned in dispatches. When hostilities ceased he returned home but, being unmarried, he was not discharged until July 1946.

He then commenced in a general practice with his eldest brother Drummond until 1955 when he restricted his work to diseases of children, with consulting rooms at Bankstown and in Macquarie Street. In 1947 he was appointed as an honorary assistant physician at the Royal Alexandra Hospital for Children, becoming a full physician in 1954. He enjoyed his work at this hospital and was liked by his students. He was also an honorary physician at the Canterbury District Memorial Hospital and later honorary consultant paediatrician. In addition he was honorary paediatrician at the Bankstown District Hospital. He was known as a conscientious, sound children's physician and was highly regarded by his patients and their parents. He was never one to speak up at meetings, clinical or otherwise, and never published. He did enjoy convivial gatherings and could, after much persuasion, produce an amusing after- dinner speech.

In 1946, shortly after his discharge from the Army, he married Joan, a daughter of Thomas Lipscomb, president of the British Medical Association, New South Wales branch and of the Royal Australasian College of Surgeons. They had two daughters both of whom graduated at the University of Sydney, one in science and the other in architecture. He had a happy relationship with his family, who supported him in his last illness. He played a regular game of golf on Sundays at the Royal Sydney Golf Club which was a high point of his week.