During the 1950s and on into the 1980s, Johnston was one of the foremost coal economists in the United States.
He entered the coal business in 1940 with Hickman, Williams & Co. He joined Appalachian Coals in 1948 as economist and was made executive vice president in 1958. He was also the long time editor of the old ACI Bulletin, published for the coal industry.
In 1964, Johnston joined Island Creek Coal as manager of economic services, a position he held until his retirement in 1976. After that time he continued to provide economic consulting services to various national energy companies.
He also served as chairman of the Market Forecast group for NCA, a predecessor organization of NMA; participated in a presidential trade commission in 1964; and was president of the Cleveland Economist Club in the early 1970s.
