Axel was born in Hamburg, Germany. At school he was good at art, but didn't think of a career in illustration until he won a cuddly purple cow in a drawing competition. He moved to England in 1982 to study illustration at the Bath Academy of Art, and then set up home in London.
He was the illustrator for Julia Donaldson's first picture book, A Squash and a Squeeze - the start of a hugely successful partnership. Their bestselling modern classic, The Gruffalo, has sold millions of copies. His books have been translated into 42 languages.