Roberts was born in London, the son of a superintending inspector of income tax. He was educated at Bedford School, and Owens College, Manchester, England.

Near the end of 1876 Roberts took a steerage passage to Australia and landed at Melbourne in January 1877. The next three years were spent in obtaining colonial experience, mostly on sheep stations in New South Wales, and Roberts then returned to London. For a time he worked in the war office and other government departments, but again went on his travels and had varied occupations in the United States and Canada between 1884 and 1886. He later travelled in Oceania, Australia, South Africa, amongst other parts of the world.

Roberts used his experiences freely in his books, the first being The Western Avernus(1887). Roberts began his long series of novels and short stories in 1890. Of his novels, Rachel Marr (1903) was highly praised by William Henry Hudson, and The Private Life of Henry Maitland (1912), based on the life of George Gissing the novelist, was possibly his best known book. Roberts also wrote essays, biography, drama and verse, and did some competent work in biology. He married Alice, daughter of A. R. Selous, and died in London aged 84 on 8 June 1942.

Approximately 80 of Roberts' books are recorded in E Morris Miller's Australian Literature. He was only a few years in Australia, but there are many Australian references both in his novels and his short stories.

Short Stories include:

• King Billy of Ballarat and Other Stories, Lawrence & Bullen (London), 1892 (including: "Father and Son")
• Red Earth, Lawrence & Bullen (London), 1894 (including: "Wide Bay Bar".)
• The Keeper of the Waters, Skeffington & Son (London), 1898 (including: "The Anticipator".)
• Midsummer Madness, Eveleigh Nash (London), 1909 (including: "The Bood Fetisch")