Born in the suburbs of London, Jim (James) Holdaway attended Kingston art school before he was drafted in the East Surrey Regiment in 1945. Three years later, he worked in the advertising and illustration business, among others for the French market and the London publisher Kensington. Afterwards, his first comics appeared in Gallant Detective in 1952 ('Inspector Hayden', 'Lex Knight').
From 1953, Holdaway expanded his activities and worked on series like 'Captain Vigour', 'Dick Hercules, and 'Steve Samson', as well as strips for Football Comics. Later on, he also contributed to Tit-Bits Science Fiction Comics and made the western series 'Cal McCord' and 'Cliff McCoy' for Comic Cuts. In 1956, he made 'The Red Rider' for Swift and 'Davy Crockett' for Mickey's Weekly.
In 1957, he took over 'Romeo Brown' from Alfred Mazure in the Daily Mirror. It was thanks to this series that Jim Holdaway became famous. It was his first collaboration with writer Peter O'Donell, with whom he created the female secret agent 'Modesty Blaise' in 1963. This series, a female version of James Bond, started in The Evening Standard in 1963. Filmmaker Joseph Losey made a feature film out of the character in 1966.