After graduating in 1994, Walker worked as a freelance photography assistant in London before moving to New York City as a full-time assistant to Richard Avedon. On returning to England, he initially concentrated on portrait and documentary work for UK newspapers. At the age of 25, he shot his first fashion story for Vogue.[1]

Walker staged his first major exhibition at the Design Museum, London in 2008.[2] This coincided with the release of his book Pictures published by teNeues.[3]

In 2010 Walker's first short film, The Lost Explorer (BBC Films, 2010) was premiered at Locarno Film Festival in Switzerland.

Walker's Story Teller was exhibited at Somerset House in 2012[4] and published as a book by Thames and Hudson, designed by Ruth Ansel.[5]

In 2013 The Bowes Museum in Durham exhibited Walker's photographs, curated by Greville Worthington, of work beyond the pages of Vogue and Vanity Fair.[6]

Walker lives in London.