Jenkins served as a lieutenant with the Royal Field Artillery during and after the First World War (1914-1920, and again in 1925).
He entered the colonial service in Nyasaland in 1925, before becoming Solicitor General of Northern Rhodesia in 1936.
[6] He then served as Attorney General of Fiji from 1938 to 1945;[7] towards the end of his term, he was appointed Chief Justice of Nyasaland on 8 November 1944.
[8] As Chief Justice, he headed a commission of inquiry into a riot that had taken place at Zomba Prison in November 1949.
He was criticised by both Sir Geoffrey Colby, the Governor of Nyasaland, and the Legislative Council, for allegedly paying undue attention to "matters of relatively minor significance" and of ignoring what they believed was the fundamental cause of the problem: the breakdown of discipline in the prison over the previous two years.