Migrating to Adelaide in 1884, Fred Johns joined the literary staff of The Register in 1885, and from 1914 was Chief of the Hansard Staff in South Australia. He edited The Navy Messenger (Adelaide, 1921-1923) for the SA Branch of the Navy League.
Although Johns published a book of original verse and the collection Journalist's Jottings in the 1920s, he is best known for his biographical research. He compiled a volume of biographies of contemporary Australians, Johns' Notable Australians (1906) which was continued as Fred Johns' Annual, Who's Who in the Commonwealth of Australia and Who's Who in Australia, the title under which it continues today. He also published An Australian Biographical Dictionary (1934).
In 1932 he bequeathed to the University of Adelaide the sum of one thousand five hundred pounds for the purpose of founding a scholarship to be called the 'Fred Johns Scholarship for Biography' to encourage the writing of biographies on eminent Australians.