His first stories were mainly boys adventures about canoeing, fishing, camping, based on his real life experiences.

In the early 1890s, William Murray Graydon began to write stories and novels of foreign and historical adventure.

One of his earliest popular creations was wild beast purveyor Matthew Quin, who appeared in about 30 short stories in the United States between January 1898 and November 1902.

[3] William Murray Graydon was one of the most prolific Sexton Blake authors, penning over two hundred and sixty tales over the course of his long career.

[3] He moved Blake to Baker Street, and created two greatly loved recurring characters: Blake's wise and ferocious bloodhound Pedro in The Dog Detective in Union Jack #100, and his comical landlady Mrs. Bardell in The House of Mystery in Union Jack #97.

His other creations include Inspector Widgeon, American detective Fenlock Fawn, British Secret Service agent Cavendish Doyle, and master criminals Basil Wicketshaw and Laban Creed.

Perhaps his best remembered works are Sexton Blake in the Congo and Across the Equator, two long serials that ran in Boys' Friend in 1907.