James Eric Johnson was born in Moonta, South Australia on 21 January 1917. His mother died during childbirth and after his father died in active military service Johnson was raised by his grandparents. From an early age Johnson showed an interest in rocks and minerals, and he would spend time fossicking around the mines and talking to the old miners.

Johnson's formal education appears to have been limited to the Moonta mines school. However, he would gain an enormous self-taught knowledge of mineralogy through experience in the mining industry.

During the Depression, Johnson undertook a number of jobs. His first job was shovelling gypsum at Stenhouse Bay circa 1930. He was later employed as the foreman at the Triple Chance Mine near Broken Hill, New South Wales, a timber cutter, and in salt production. Johnson generally preferred work related to the mining industry. In 1950, he formed a Feldspar syndicate with two others to work Emery’s Hut in the Olary region of South Australia.

Johnson joined the Mines Department of South Australia in 1953, working as a Technical and Field Assistant. In this capacity he undertook prospecting and mapping at Crocker Well, Mt Painter, Eyre Peninsula and The Musgrave Ranges.

In 1956, Johnson left the Mines Department to join Geosurveys of Australia Pty Ltd, a private consulting firm set up by former employees of Mines Department under RC Sprigg. His work there included trips into the north west of South Australia, including the Tomkinson Ranges.

Johnson returned to the Department of Mines in 1960. He was involved in regional mapping activities, and his name appears as co-author on six geological maps published by the Department.

In 1968, Johnson returned again to Geosurveys, where he remained until ill-health forced him to retire in 1971. He wrote to a colleague in October, 1971, "the surgeons now tell me that my operation is too drastic and aren’t going to do it... this means that I am now retired from field work, a time which comes to all of us but which I still find hard to accept" (AA 159/2/60/55).

In 1972, Johnson commenced work as an Honorary Research Worker at the South Australian Museum and later became an Honorary Associate in Mineralogy in 1974. At the South Australian Museum Johnson worked on the mineral collections he had donated, including at least three meteorites. He also undertook field research throughout this period, including investigation of Reaphook Hill Phosphates. During this time Johnson was engaged in swapping minerals with amateur and professional mineralogists from all over the world.

Johnson also donated many objects relating to Australian Aboriginal material culture such as stone tools and spears.

Johnson died of throat cancer on 19 October 1983 and was cremated at Centennial Park Cemetery in Adelaide, South Australia, on 4 November 1983.

Johnson was a member of the Adelaide Gem and Mineral Club. He gave lectures and led many field trips for the Club. He was also a founding Member of the Mineralogical Society of South Australia, which later named a biennial memorial medal after him.

Johnson prepared at least fifty seven published and unpublished reports with the Department of Mines, as well as reports published at the South Australian Museum, Geosurveys, and various scientific journals. His research was used as the basis for the 1983 Catalogue of South Australian Minerals, published by the Department of Mines after his death on 19 October 1983. The Department also lists Johnson as the co-author of six published maps.

A large body of Johnson's records donated to the South Australian Museum refer to Australian Aboriginal archaeological sites. Johnson was particularly interested in stone artefacts he found at these sites, and drew highly detailed diagrams of them in his notebooks. He also attempted to reproduce rock art pictures. He would have come into contact with these sites during field surveys for the Department of Mines and Geosurveys. These sites covered a large area, stretching from Western Australia, across the South Australian and Nothern Territory border, and into the Broken Hill area of New South Wales.

Most of this anthropological material dates from before Johnson's retirement from professional mineralogical work in 1972. This leads to speculation that the majority of his notes relating to geology and mineralogy that were made during his career remained with his employers, and that he personally only kept notes relating to his amateur interest in aboriginal artefacts.