While at Dulwich he produced a comic called The Junior. In 1942 he had his first professional work, "Magical Monty" in All Fun Comics, published, at the age of 14. Later the same year he began contributing to DC Thomson's humour comics, including The Dandy.
In 1944-45 he was junior cartoonist for the newspaper Reynold's News, and in the post-war years he and Monkhouse published a variety of comics, often one-offs, in a variety of genres, despite doing his national service in the RAF in 1946-48. He created superheroes like Mr Muscle (Dynamic Comics, 1945) and Streamline (Streamline Comics, 1947), westerns like "Ace High" Rogers versus Redmask (1946), "Bill Elliott in Republic's Old Los Angeles" (The Sheriff #3, 1948) and "Roy Rogers" (The Sheriff Comics, 1950), and humour comics like Panto Pranks, Fizz Comics and Star Comics (all 1949). In 1949 he published the detective series Ray Regan, drawn by Ron Embleton, for which he drew a backup strip, "Tiger-Man". In the late 1940s he and Monkhouse toured the South-East of England as a comedy double-act with the West Bees Concert Party.
In the 1950s he started drawing humour strips for the Amalgamated Press, including "Our Ernie", "Stonehenge Kit the Ancient Brit" and his own character, "Steadfast McStaunch", for Knock-Out. He and Monkhouse set up their own publishing company, Streamline, publishing reprints of American superhero comics.
In 1953 he began an association with Mick Anglo, working on Anglo's science fiction title Space Comics. He joined Anglo's studio the following year, where he worked on Marvelman (1954-?), Annie Oakley (1957-58), Gunhawks Western (1960-61) and Captain Miracle (1960-61). He drew "News of the Universe Television Service", "Dan the TV Man" and "Jester Moment" for the Anglo-edited TV Tornado (1967-68), and contributed humour strips to Super DC (1969-70), packaged by Anglo.
In the 1950s he wrote for TV and radio, including scripting for Morcambe and Wise.
He was one of the UK's leading historians of comics. He published many reference works, including Discovering Comics (1971), The British Comics Catalogue, 1874-1974) (1974), Victorian Comics (1976), British Comics, Story Papers, Picture Libraries, Girls Papers, American Reprints, Facsmilies, Giveaways Price Guide (1982)
He argued that "there is no point where we can pick up a paper and declare it Comic Number One", but traced the antecedents of comics to the humorous periodical The Comick Magazine (1796), which included prints by William Hogarth which combined into a narrative sequence, through "the first continuing cartoon hero" Dr Syntax, created by Thomas Rowlandson in The Poetical Magazine (1809) and the first caricature magazine, The Glasgow Looking Glass (1825). He argued that comics proper began with Ally Sloper in Judy (1867), and the first identifiable comic was Funny Folks (1874).
He launched Ally Sloper magazine in 1976, reprinting early comics combined with new material, seeking to ensure a modern readership had an awareness of early comic history, which only lasted four issues. He also initiated the Ally Sloper Prize the same year. In 1977 he founded the Society for Strip Illustration. He was also a historian of film, radio and music hall, writing a number of important reference works in these fields.
He died on 18 May 2000.
- Mary Cadogan, "Gifford, Denis (1927–2000)", Oxford Dictionary of National Biography, Oxford University Press, 2004, accessed 23 May 2014
- Librarything.com - Bibliography of Denis Gifford; p. 913. Retrieved 17 December 2011.
- Obituaries: Denis Gifford; The Daily Telegraph 25 May 2000.
- Obituaries: Denis Gifford; The Guardian (26 May 2000). Retrieved 14 December 2011.
- Comics Historian Denis Gifford Dies Age 72; The Comics Journal; Issue #224 (June 2000).
- Tony Fletcher; Obituary: Denis Gifford; The Independent (5 June 2000).
- Tom Vallance; Obituary: Denis Gifford; The Independent (24 May 2000).
- Denis Gifford on Wikipedia
- Comics art and writing of Denis Gifford on Wikipedia
- Denis Gifford on Lambiek
- British Cartoon Archive - Denis Gifford. Retrieved 21 December 2011.
- Missing Link fansite, "The Missing Link Pays a Personal Tribute to Denis Gifford". Retrieved 14 December 2011.