Almond was born and raised in Felling and Newcastle in post-industrial North East England and educated at the University of East Anglia. When he was young, he found his love of writing when some short stories of his were published in a local magazine. He started out as an author of adult fiction (self publishing 500 copies of his first novel Sleepless Nights) before finding his niche writing literature for young adults.

His first children's novel, Skellig (1998), set in Newcastle, won the Whitbread Children's Novel of the Year Award and also the Carnegie Medal. It has been adapted into a stage play, film and opera.

His subsequent novels are: Kit's Wilderness (1999), Heaven Eyes (2000), Secret Heart (2001), The Fire Eaters (2003) which won the 2003 Whitbread Awards, Clay (2005), Raven Summer (2008), and The Savage (2008) a children's book whose subject matter is written more towards young adults and adults. His first play aimed at adolescents, Wild Girl, Wild Boy, toured in 2001 and was published in 2002.

His works are highly philosophical and thus appeal to children and adults alike. Recurring themes throughout include the complex relationships between apparent opposites (such as life and death, reality and fiction, past and future); forms of education; growing up and adapting to change; the nature of "the self". He has been greatly influenced by the works of the English Romantic poet William Blake.

He is an author often suggested on National Curriculum reading lists in the United Kingdom and has attracted the attention of academics who specialise in the study of children's literature.

Almond currently lives with his family in Northumberland, England. Since 2007 he has been a Visiting Professor in Creative Writing at Nottingham Trent University.

In November 2008 he was a guest on Private Passions, the biographical music discussion programme on BBC Radio 3.

His short story "The Knife Sharpener" appeared in The Sunday Times on 25 January 2009 and The Savage was given away free as part of the Liverpool Reads event.

In 2010 he was awarded the prestigious Hans Christian Andersen prize for lifetime achievement in children's writing.