Donald Rooum was born in Bradford. He registered as a conscientious objector but was pressurised by his family into doing two years military service, starting January 1947. A resettlement grant following his discharge allowed him to study commercial design at Bradford Regional Art School from 1949 to 1953. Rooum's portrait by Frank Lisle, one of his lecturers of the time, is in Wakefield Gallery.
From 1954 to 1966 Rooum worked as a layout artist and typographer in London advertising agencies, then as a lecturer in typographic design at the London College of Printing until 1983. He studied life sciences at the Open University from 1973 to 1979, and was awarded a first class degree in 1980. He was elected Member of the Institute of Biology (incorporated into the Society of Biology in October 2009) and became a chartered biologist in 2004.
Rooum lived with Irene Brown from 1954 to 1983 and they had four children: Josephine Anne (born 1956), Penelope Jane (born 1958 died 1960), Mathew Donald (born 1960) and Rebecca Jane (born 1962).
Rooum says that he first became interested in anarchism in 1944 when he visited Speaker's Corner in London while on a Ministry of Food scheme which used schoolboys to pick hops in Kent. He subscibed to War Commentary, thus beginning a connection with Freedom Press which has continued for over sixty years. During that time he has been a writer for and an editor of Freedom, the name to which War Commentary reverted after the end of the Second World War.
In 1949, Rooum began to raise his profile in activist circles, participating the annual anarchist summer school. The working title of Frank Lisle's 1952 portrait was The Anarchist. Rooum became an outdoor speaker Market Street, Bradford, then at Speaker's Corner. He was a founding member of the Malatesta Club, an anarchist social club and venue that opened in London on May Day 1954. Rooum and Irene Brown worked as volunteers there.
Role in the Challenor affair 
On 11 July, Rooum demonstrated against the royal party at Claridge's hotel. His banner "Lambrakis RIP" was confiscated by a police officer and read by four plain clothes men. According to Rooum he asked "Can I have my banner back?"
Rooum: "This big one with the short-back-and-sides stepped forward. 'Can you have your what back?'
"He smiled at me. 'You're fucking nicked, my old beauty,' he said, and gave me a terrific clout on the ear."
At the police station, the arresting officer, Detective Sergeant Harold Challenor, "took from his pocket a screwed-up newspaper, which he opened with a flourish. Inside was a piece of brick. His smile widened. 'There you are, my old beauty. Carrying an offensive weapon. You can get two years for that.'"
Rooum was a member of the National Council of Civil Liberties. He had, by good fortune, read some material on forensic science and gave his clothes to his defence solicitor Stanley Clinton Davis for analysis. He convinced the magistrate that, because no brick dust was found in his pocket, no brick could have been there at the time of the alleged offence. There followed a public enquiry that criticized the police and led to the imprisonment of three officers. Rooum received £500 compensation (£7,900 at 2011 value) and other convictions were overturned.
Challenor was deemed mentally unfit to plead and was committed to Netherne mental hospital. A subsequent enquiry found that he had probably been suffering from the onset of paranoid schizophrenia for some months before the incident. The lack of any successful prosecution against him was seen by some as evidence of further establishment corruption.
In 1952, Philip Sansom invited Rooum to draw a regular cartoon strip for The Syndicalist and he contributed Scissor Bill. The name derived from an IWW name for a bosses' yes-man. From 1960, his cartoons started appearing in such outlets as She, The Daily Mirror, Private Eye and The Spectator. Rooum has had a long relationship, with interruptions, with Peace News, his first work appearing for them in 1962. Originals of his cartoons for Peace News up to 1971, together with some for The Spectator, are stored at the British Cartoon Archive.
In 1974, Sansom invited Rooum to provide a cartoon for a monthly magazine he was working on,Wildcat. Rooum created a character of the same name. Wildcat ceased publication in 1975 but in 1980, when Sansom was again working on Freedom, he persuaded Rooum and the editorial collective to revive the Wildcat comic strip, which has been a feature ever since.
Rooum has drawn the Sprite strip for The Skeptic magazine since 1987. He has illustration several book, including Don't you believe it! by John Radford. An exhibition of Rooum's work was held at Conway Hall in 2008.
- Wildcat Anarchist Comics, 1985, London, Freedom Press, ISBN 0-900384-30-1
- "Gandalf's Garden" in: Outrageous Tales from the Old Testament ed: Tony Bennett, 1987, London, Knockabout Comics, ISBN 0-86166-054-4
- Wildcat Strikes Again, 1989, London, Freedom Press, ISBN 0-900384-47-6
- Wildcat: ABC of Bosses,1991, London, Freedom Press, ISBN 0-900384-60-3
- Health Service Wildcat, 1994, London, Freedom Press, ISBN 0-900384-73-5
- Twenty Year Millennium Wildcat: Anarchist Comics 1999, London, Freedom Press, ISBN 0-900384-97-2
- Wildcat: Anarchists Against Bombs, 2003, London, Freedom Press, ISBN 1-904491-01-4
- Wildcat Keeps Going, 2011, London, Freedom Press, ISBN 978-1-904491-14-9
As writer 
- "Sir Cyril Burt and typography: a re-evaluation" James Hartley and Donald Rooum 1983 British Journal of Psychology 74, 203-212
- "Karl von Frisch and the 'Spot Codes' for marking insects". 1989, Bee World 70:120-126
- What Is Anarchism?: An Introduction, London, Freedom Press, ISBN 0-900384-66-2
- Introduction to Mutual Aid: A Factor of Evolution (4th Edition) by Peter Kropotkin London, Freedom Press, 2009 ISBN 1-904491-10-3
As illustrator 
- Classics of Humour (Dickens, Charles; O'Brien, Flann; Saki; Thurber, James; Twain, Mark; Waugh, Evelyn; Wilde, Oscar, Wodehouse, P G, et al., authors); O'Mara, Michael (ed), Donald Rooum (Illustrator) 1976 Book Club Associates ASIN B0010S72HK, 1976 Constable and Company ISBN 0-09-461440-7
- English Lessons One Michael Hapgood (author), Donald Rooum (illustrator); 1981 Heinemann Educational Books ISBN 0-435-10400-4
- The innocent Anthropologist by Nigel Barley (author), Donald Rooum (illustrator); 1983 British Museum Publications !SBN 0714180548
- Don't You Believe It!: Some Things Everyone Knows That Actually Ain't So by John Radford (Author), Donald Rooum (Illustrator), London 2007, Stepney Green Press, ISBN 0-9554431-0-5
- Citizenship Cartoons (2003) by Alastair Gunn (Author), Donald Rooum (Author) Classroom Resources ISBN 1-84106-789-X
As editor 
- "Freedom": A Hundred Years, October 1886-October 1986 London, Freedom Press, 1986 ISBN 0-900384-35-2
- March to Death: Drawings By John Olday, London, Freedom Press, 1995 ISBN 0-900384-80-8
- Sansom, Philip "Introduction" in Wildcat Anarchist Comics by Donald Rooum, London, Freedom Press, pp.2-12.
- Portrait of Donald Rooum by Frank Lisle", Object of the Month, April 2008 Wakefield Council
- Rooum, Donald "Freedom, Freedom Press and Freedom Bookshop" in Information for Social Change Number 27, Summer 2008, pp.29-36 ISSN 1364-694X
- Rooum, Donald, "I've dislodged a bit of brick", Anarchy, No.36, Vol.4. No.2, February 1964
- Link to article on Challenor, mentioning Rooum's role in exposing him
- James Morton (1993) Bent Coppers pp.118-9
- Driver, C., The Disarmers, Hodder and Stoughton, London, 1964
- Parliamentary question by Shirley Summerskill to Home Office ministers 
- Parliamentary question to Attorney General re Challenor by Arthur Lewis
- The Challenor Case by Mary Grigg; Harmondsworth 1965 Penguin Books
- Report of Enquiry" by Mr A.E.James, QC, 1965 HMSO, Cmnd 2735
- The Jester and the Court by Edward Robey; London 1976 William Kimber & Co. Ltd ISBN 0-7183-0494-2
- Tanky Challenor, SAS and the Met by Harold Challoner with Edward Draper, London 1990, Leo Cooper ISBN 0-85052-142-6
- Sybil's Nest - A page containing examples and details of how to get Wildcat books.
- Cartoons placed online by the British Cartoon Archive
- Portrait of Rooum by Frank Lisle.