He will be in charge of driving its global expansion as well as overseeing UK marketing. Palmer, who moved into consultancy and took on a non-executive role at Green & Black's soon after its acquisition by Cadbury in 2005, is now the organic chocolate company's most senior marketer.
His return to the firm coincides with the departure of the UK marketing director Carol Welch, who joined from Cadbury last year. She is believed to have secured a new role.
Palmer said UK promotional spend for 2008 would increase by 25% to £7m and the brand would be using digital and outdoor for the first time in addition to press.
'Next year will see a record amount of spend,' he said. 'We are looking at how we can reach consumers in other ways.'