Martin spent time in various countries working as a cowboy, gold prospector and wild-horse trader, among other occupations. During the Second World War he lived in Nottingham, working for the Ambulance Service.

He began writing full-time after the war, publishing his first novel in 1949 under the name "Hank McCoy". He wrote more westerns over the next few years under various pseudonyms, began writing various genre children's novels in 1953 and wrote a science fiction novel The Wheel in the Sky (1954). He also wrote spin-off novels, short stories, non-fiction books and ghost-wrote several sports novels.