Rosen was born into a Jewish family in Harrow, Middlesex, the son of communist parents. His father Harold (1919–2008) was born in Brockton, Massachusetts. His mother was Connie (nee Isakofsky) Rosen (1920-1976). Harold Rosen settled in the East End of London at the age of two, when his mother returned to the country of her birth. While a member of the Young Communist League, Harold met Connie Isakofsky, his future wife and Rosen's mother, in 1935. Harold was a secondary school teacher before becoming a professor of English at the Institute of Education in London, and Connie was a primary school teacher before becoming a training college lecturer; she also broadcast for the BBC. Producing a programme featuring poetry, she persuaded her son to write for it, and used some of the material he submitted. Their ancestors came from Poland, Russia, and Romania. Rosen was raised in Pinner, Middlesex, and went to various state schools in Pinner and Harrow, and Watford Grammar School for Boys; having discovered the range of Jonathan Miller, he thought "wouldn't it be wonderful to know all about science, and know all about art, and be funny and urbane and all that". Subsequently, in his own words:
I went to Middlesex Hospital Medical School, started on the first part of a medical training, jacked it in and went on to do a degree in English at Oxford University. I then worked for the BBC until they chucked me out and I have been a freelance writer, broadcaster, lecturer, performer ever since – that's to say since 1972. Most of my books have been for children, but that's not how I started out. Sometime around the age of twelve and thirteen I began to get a sense that I liked writing, liked trying out different kinds of writing, I tried writing satirical poems about people I knew.
After his studies at Wadham College, Oxford, and graduation in 1969, Rosen became a graduate trainee at the BBC. Among the work that he did while there in the 1970s was presenting a series on BBC Schools television called WALRUS (Write And Learn, Read, Understand, Speak). He was also scriptwriter on the children's reading series Sam on Boffs' Island. But Rosen found working for the corporation frustrating: "Their view of 'educational' was narrow. The machine had decided this was the direction to take. Your own creativity was down the spout."
Despite previously having made no secret of his radical left-wing politics when he was originally interviewed for a BBC post, he was asked to go freelance in 1972, though in practice he was sacked despite several departments of the BBC wishing to employ him. In common with the China expert and journalist Isabel Hilton among several others at this time, Rosen had failed the vetting procedures which were then in operation. This long-standing practice was only revealed in 1985, and by the time Rosen requested to access his files, they had been destroyed.
In 1974 Mind Your Own Business, his first book of poetry for children, was published. In due course, Rosen established himself with his collections of humorous verse for children, including Wouldn't You Like to Know, You Tell Me and Quick Let's Get Out of Here.
Educationalist Morag Styles has described Rosen as "one of the most significant figures in contemporary children's poetry". He was, says Styles, one of the first poets "to draw closely on his own childhood experiences [...] and to 'tell it as it was' in the ordinary language children actually use".
Rosen played a key role in opening up children's access to poetry: both through his own writing and with important anthologies such as Culture Shock. He was one of the first poets to make visits to schools throughout the UK and further afield in Australia, Canada and Singapore. His tours continue to enthuse and engage school children about poetry in the present.
In 1993, Rosen gained an M.A. in Children's Literature from the University of Reading; he also holds a Ph.D. from the University of North London.
Rosen is well established as a broadcaster, presenting a range of documentary features on British radio. He is the presenter of BBC Radio 4's regular magazine programme Word of Mouth which looks at the English language and the way it is used.
The English Association gave Michael Rosen's Sad Book an Exceptional Award for the Best Children's Illustrated Books of 2004, in the 4–11 age range. The book was written by Michael Rosen and illustrated by Quentin Blake. It deals in part with bereavement, and followed the publication of Carrying the Elephant: A Memoir of Love and Loss which was published in November 2002 after the death of his son Eddie (age 18), who features as a child in much of his earlier poetry. In 2004 Rosen published This Is Not My Nose: A Memoir of Illness and Recovery, an account of his ten years with undiagnosed hypothyroidism; a course of drugs in 1981 alleviated the condition.
Rosen has been involved in campaigning around issues of education and for the Palestinian cause. He has written columns for the Socialist Worker newspaper and spoken at conferences organised by the Socialist Workers Party. He stood for election in June 2004 in London as a Respect Coalition candidate. He is a supporter of the Republic campaign. Rosen supported Jeremy Corbyn in his campaign for the Labour Party leadership election in 2015, and was a signatory to a letter criticising The Jewish Chronicle 's reporting of Corbyn's association with alleged antisemites.
In August 2010 Rosen contributed to an eBook collection of political poems entitled Emergency Verse - Poetry in Defence of the Welfare State edited by Alan Morrison
In 2011 he collaborated with his wife, Emma-Louise Williams, to produce the film 'Under the Cranes', with Rosen providing the original screenplay (a 'play for voices' called 'Hackney Streets') which Williams took as a basis with which to direct the film. It premiered at the Rio Cinema, Dalston, London on 30 April 2011 as part of the East End Film Festival.
He was formerly a Visiting Professor of Children's Literature at Birkbeck, University of London, where he taught Children's Literature and has devised an MA in Children's Literature, which commenced in October 2010. Since September 2014 he has been at Goldsmiths, University of London as Professor of Children's Literature in the Department of Educational Studies teaching an MA in children's literature.
He is also a patron of the Shakespeare Schools Festival, a charity that enables school children across the UK to perform Shakespeare in professional theatres. Rosen was the subject of the BBC Radio 4's Desert Island Discs programme on 6 August 2006.
Rosen and Helen Oxenbury collaborated on the book We're going on a Bear Hunt which won a Nestle Smarties Book Prize in 1989, and in 2014 the publisher, Walker Books, celebrated the 25th anniversary by breaking a Guinness World Record for Largest Reading Lesson.
Rosen has been married three times, and is the father of five children and has two stepchildren. Eddie, his second son, died at age 18 of meningitis in 1999. His death was the inspiration for Michael Rosen's Sad Book (2004). Rosen lives in North London with his third wife, Emma-Louise Williams, and their two children.
Rosen was appointed the sixth British Children's Laureate in June 2007, succeeding Jacqueline Wilson, and held the honour until 9 June 2009, succeeded by Anthony Browne. Rosen signed off from the Laureateship with an article in The Guardian, in which he said, poignantly: "Sometimes when I sit with children when they have the space to talk and write about things, I have the feeling that I am privileged to be the kind of person who is asked to be part of it". Also in the summer of 2007 he was awarded an Honorary D.Litt at the University of Exeter.
On 19 January 2008 Rosen was presented with an Honorary Doctorate of Letters from the Tavistock and Portman NHS Trust and the University of East London at a ceremony held at the Institute of Education. On 5 November 2008 he was presented with an Honorary master's degree at the University of Worcester, then on 18 November 2008 he was presented with the Chevalier de l'Ordre des Arts et des Lettres (Knight of the Order of Arts and Literature) by the Government of France at the French Ambassador's residence in London.
On 2 April 2010 Rosen was given the Fred and Anne Jarvis Award from the National Union of Teachers for "campaigning for education". On 22 July 2010 he was awarded an honorary degree of Doctor of Education (DEd) by Nottingham Trent University.
On 5 April 2011 Rosen was awarded an Honorary Doctorate at the Institute of Education, University of London, and on 20 July 2011 he was awarded the honorary degree of Doctor of Letters by the University of the West of England.
Rosen was selected to be the guest director of the Brighton Festival in May 2013.