James Erskine Sewell was born on 7 July 1906 in Elsternwick. His father, Percy Sewell, was an importer and a keen tennis player, which no doubt laid the basis for James's later excellence in this sport. His secondary education was gained at Haileybury College and Melbourne Grammar School where he distinguished himself as house captain, played in the first eleven and did well at boxing and tennis. He and his partner won the schoolboys' tennis championship in 1924.

He attended Melbourne University to do his medical course, no doubt influenced in his choice of profession by his uncle, Dr Sidney (later Sir Sidney) Sewell, an eminent consultant physician of the day. While resident in Trinity College he rose to the status of senior student, and gained a blue in Rugby and a half-blue in athletics. In his final year he was invited to join the training squad for the Australian Rugby touring side but declined this honour. He graduated in 1930 with first-class honours in both medicine and surgery. The character traits which were to distinguish his life were well established by now. He had a strong determined nature softened by a pleasant perseverance and a natural charm which was quite disarming; nevertheless he was uncompromising where matters of principle were involved.

After residencies at the Melbourne and Children's Hospitals he was appointed Beaney Scholar in histology and pathology in 1933 and in 1934 took his Doctorate of Medicine. In August 1936 he married his cousin, Joan Sewell, the daughter of Sir Sidney Sewell, and until his untimely death they enjoyed a very happy life together. Both Jim and Joan shared a common interest in skiing, one which continued undiminished until his demise. When in England in 1937, Jim gained the Membership of the Royal College of Physicians and at the London Hospital he came under the spell of that erudite clinician, Dr Donald Hunter.

After his return to Melbourne in 1939 he became a Member of The Royal Australasian College of Physicians. In the Second World War he served in the Middle East with the 2/7 Australian General Hospital in Egypt, gaining a mention in dispatches for outstanding service. He was promoted to lieutenant-colonel and served in Ceylon, New Guinea and Queensland as OC medical at various hospitals, where his drive and professional skills were greatly appreciated. After his discharge from the Army, he commenced private consultant practice at 85 Spring Street, Melbourne.

He received a Carnegie Travelling Fellowship to the United States in 1948, and was elected to Fellowship of The Royal Australasian College of Physicians in that year. His hospital appointments included honorary physician to inpatients, Alfred Hospital, physician to the Austin Hospital and visiting physician to the Heidelberg Repatriation Hospital. He found time to further the work of the Alcoholism Foundation of Victoria. Amidst the pressure of his numerous commitments he gained a reputation for always being late; but he was at pains to inform any critic, that he was never late for a train or a plane.

He suffered a catastrophic myocardial infarction on 9 November 1964 and was dead on arrival at the Alfred Hospital. He was survived by his wife Joan and children Michael and Jill.