His decision comes as newly installed chief executive, David Abraham, unveils a restructure of the broadcaster, which includes plans to combine its corporate relations, marketing and press and publicity teams into a single division under a new senior director.
Baker, controller of press & publicity, will stay with the broadcaster while a head for the combined division is recruited,
He has headed Channel 4's press office since 2000, is planning to take a break from public relations to concentrate on freelance writing projects.
Baker said: 'David has bold and imaginative plans for Channel 4 and he's kindly made clear there is still a place for me here. But having worked with three previous chief executives and talked myself hoarse over more than a decade, this feels the right time to switch off my Blackberry. I feel privileged to have worked for such a unique creative institution through an extraordinary period in its history and, at present, I can't quite imagine doing a similar job elsewhere, which is why it feels right to take a step back for the time being.'
Abraham added: ‘Matt has made a huge contribution to Channel 4 over the last 12 years and, in my first few weeks in the job, it has been clear that Matt is one of the top professionals in his field. I would like to thank him on behalf of Channel 4 and wish him all the very best in his future projects.'
Baker joined Channel 4 as chief press officer and deputy head of corporate affairs in August 1998. Prior to joining Channel 4 he was editor of trade magazine Broadcast and media editor for the relaunch of Sunday Business.