He replaces Tessa Jowell, who will now be Olympics Secretary.
The role means Purnell will now be in charge of areas including film co-production treaties, and he will also have ultimate sign-off on the new Cultural Test For British Film, which is now administered by the UK Film Council.
Purnell, a rising star among young Labour leaders, had served as Creative Industries Minister in the Department of Culture Media and Sport from May 2005, before moving to become Minister of State for Pensions in May 2006.
Also, with Brown's cabinet shakeup, Shaun Woodward has moved from his post as Creative Industries and Tourism Minister to Northern Ireland Secretary.
A new Creative Industries Minister hasn't been named yet.