Richard Thorold Grant was born in North Adelaide, the only son of William Thorold and Emily (nee Jefferson). His forebears had been pioneer pastoralists in South Australia, but his father had become better-known as a writer on rural affairs for The Australasian under the pen-name "Bendleby". During his medical course, which he started in 1913, Dick won trophies as a middle distance runner and played inter-varsity lacrosse for South Australia. Then renal tuberculosis necessitated a nephrectomy but he was still able to graduate at the end of the First World War and to achieve Membership of the Royal College of Physicians in London in 1921. After his return to Australia in 1922, he eschewed the idea of any preliminary period in general practice and commenced at once in Adelaide as a specialist physician. He then started his long association with the Adelaide Children's Hospital in various honorary appointments, at first as a pathologist and bacteriologist from 1923 to 1925; then as an assistant physician from 1926 to 1937; and finally as a physician from 1937 to 1954.

Dick married Nancy Lewis, daughter of an Adelaide ophthalmologist, on 23 February 1927 and two sons were born to the marriage. However, disaster struck in 1929 when he contracted severe generalised dermatitis as a result of wearing newly-purchased woollen underwear which apparently contained a bleach or some such chemical substance to which he was sensitive. This long illness, and the protracted litigation that followed (ultimately ending at Privy Council level) inevitably greatly disturbed his career and his family. His wife had to enter the work force and his children had to be cared for by a grandmother until he recovered. In any case, when Dick resumed his practice after those difficult years, the comparatively modest income to be derived as a general physician (with a particular interest in children) in that era meant that he was never very affluent. He lived quietly for the rest of his life at The Grange, then a less-frequented seaside suburb of Adelaide, but managed to maintain his membership of the Adelaide Club where mixing with kindred spirits was his main relaxation. Other pleasures were beachcombing along the shores of St Vincent's Gulf and seabathing near his home. He was also a keen follower of first class cricket.

He is remembered by his two sons with deep affection for his fatherly kindness and by surviving colleagues as a gentle, rather reserved, man who comported himself with dignity in his professional activities. These activities included (in addition to his consultant and teaching responsibilities at the Adelaide Children's Hospital) an appointment as visiting medical officer to the Home for Incurables (now the Julia Farr Centre); a long term as visiting physician to Estcourt House, an institution on the seafront at Tennyson where children with rheumatic heart damage spent their long convalescence; and service in South Australia during the Second World War as a consultant physician to the RAAF with the rank of wing commander. Life was never easy for Dick Grant but in spite of several major setbacks he continued in his quiet way to serve his profession and the community to the best of his ability all his days.