John Robin Jenkins was born on 11 September 1912 in the village of Flemington, near Cambuslang in Lanarkshire. His father died in 1919 and his mother worked as a cook and housekeeper to support her four children. Jenkins was awarded a bursary to attend Hamilton Academy and studied English at the University of Glasgow, graduating MA in 1936. He married in 1937 and taught in Glasgow for some years. At the outbreak of World War II he accompanied his primary school pupils on evacuation to the Borders. By now a committed pacifist, Jenkins registered as a conscientious objector, and for his war service was directed to work for the Forestry Commission. His experience of forestry work in Argyll from 1940 to 1946 is reflected in his first novel So Gaily Sings the Lark and in the better-known The Cone-Gatherers.

After the war he taught in Glasgow and Dunoon, beginning to write seriously at this time. In 1957 he moved abroad to teach in colleges in Afghanistan, Spain and Malaysia, settings which he used for several novels in the middle stages of his career. He returned to Scotland in 1968 and settled in Toward, near Dunoon, where he has lived ever since. He retired from teaching in 1970 to become a full-time writer.

In all Jenkins has produced some thirty novels. His work, though critically acclaimed, has not always sold well, but he has continued to write, telling interviewers during the 1980s that he had four or five unpublished novels in a drawer. This situation, clearly unacceptable in the case of such a distinguished novelist, has been resolved and he is now being published again and more widely appreciated. His wife died in 1990. He was awarded the OBE in 1999, and in 2002 received the Andrew Fletcher of Saltoun award, given annually by the Saltire Society, in recognition of his lifetime achievement as a writer.