Distinguished descendant of an ancient lineage, Constantine Trent Champion de Crespigny was born at Queenscliff, Victoria, second son of Philip Champion de Crespigny, general manager of the Bank of Victoria, Melbourne. His mother was Annie Frances, daughter of Philip Lamothe Snell Chauncy, a name recalled in his adopted State as Chauncy's Line. The family claims descent from hereditary champions of the Dukes of Normandy, and from the Dana family, prominent in the academic, legal, and literary world of Massachusetts.

His mother died of peritonitis when he was ten months old and he was brought up by his grandmother. He went from Brighton Grammar School to Trinity College, and graduated (with honours) MB in 1903 and ChB in 1904, followed by MD in 1906. He was a medical officer at the Melbourne and Melbourne Women's Hospitals before brief periods in general practice at Glenthompson near Beaufort (western Victoria) and Fitzroy. In 1907 he was appointed honorary physician to outpatients, St Vincent's Hospital, Melbourne. Thereafter his career fixed him firmly as the dominant physician of his generation in South Australia. In 1909 he was appointed medical superintendent of the Adelaide Hospital, from which he entered private practice in 1912.

He was first commissioned in the Australian Army Medical Corps in 1907, and left for active service in May 1915, being initially registrar and secretary, and later commanding officer of 3 Australian General Hospital. This was based at Lemnos during the Dardenelles campaign, and he then moved to command 1 Australian General Hospital at Rouen in France. He was twice mentioned in dispatches, and was made a Companion of the Distinguished Service Order. He returned briefly to Australia in 1917 and then went to London to be a consulting physician at AIF headquarters. His continuing commitment to the Australian Army Medical Corps led to the award of the Volunteer Decoration in 1930. From 1940 to 1943 he was commanding officer of 101 Australian General Hospital, Adelaide.

His dominating position as a consultant physician in Adelaide began with his appointment as an honorary physician to Adelaide Hospital in 1918, from which he retired in 1938. He was honorary physician to Adelaide Children's Hospital from 1914 to 1928. At the University of Adelaide he was part-time lecturer in practical pathology and histology from 1912 to 1919, and lecturer in clinical medicine from 1920 to 1922. From 1923 to 1937 he was lecturer in principles and practice of medicine, and served as dean of the faculty from 1929 to 1947.

His clinical work and teaching were founded on an insistence on tracing the pathological basis of disease processes. He established embryonic clinical pathology in Adelaide, in a disused shed at Adelaide Hospital, in 1909. He was a driving force in the establishment and development of the Institute of Medical and Veterinary Science, of which he was the first chairman from 1939 to his death in 1952.

He willingly accepted the responsibility to involve himself in the governance of his profession. In 1925-26 he was president of the South Australian branch of the British Medical Association, and in 1929 he presided over the medical section of the Australasian Medical Congress in Sydney. He was one of the group of physicians who founded The Royal Australasian College of Physicians in 1938, being inaugural vice-president from 1938 to 1942, president from 1942 to 1944, past president from 1944 to 1946 and continuing to serve as councillor from 1946 to 1950. His presidency was a time of great difficulty for the College, with 102 Fellows and Members on active service, and many problems with travel and communication between colleagues. To mark his presidency, he gave the College a silver loving cup and a black and silver embroidered cushion for the president's ceremonial Caduceus.

`Crep' was a towering figure in the smaller and relatively provincial Adelaide of his day. Tall and lean, with a patrician manner and formidable presence, he set for himself, and for those about him, exactingly high standards of excellence and thoroughness. His acerbic wit could be misconstrued, which no doubt troubled him, for to those who penetrated the apparent austerity of manner he projected a warm and vivid personality. He had a disconcerting habit of disappearing inside himself for what the called `the fourth dimension', and figured in many apocryphal clinical anecdotes. As one of the outstanding clinical teachers and the principal examiner of his day, he left a tradition with his former students, who in turn passed his memory to succeeding generations.

He seems not to have had a strikingly original mind, and published little more than a few clinical reports, series of cases, and a couple of orations. He wrote some newspaper articles on a visit to the United States in 1945, which make somewhat ponderous reading a generation later. He appreciated good pictures, enjoyed the spaciousness of a large garden, and showed to few an inner spirituality.

Like his father he married twice. By his first wife (Beatrix, daughter of EW Hughes of Melbourne, whom he married on 11 September 1906 at Beaufort, Victoria) he had two sons and two daughters. She died in 1943, and on 13 December 1945 he married Mary Birks Jolley, of Wentworth, New South Wales, by whom he had a daughter. His son (RG Champion de Crespigny FRACP) was a paediatrician. He died at his home in North Adelaide of hypertensive cardiovascular disease.