Cadbury chairman Roger Carr today said he would step down after shareholders approved US food giant Kraft's £11.4 billion takeover.
Mr Carr led a vocal defence of the Dairy Milk maker during the five-month takeover tussle, forcing Kraft to up its bid for the business.
"Together we have fought an excellent defence campaign and delivered substantial value to Cadbury shareholders," the chairman said.
A leaving date for Mr Carr - who first joined the Cadbury board in 2003 - has yet to be determined.
Chief executive Todd Stitzer is also to leave after 27 years with the company, with chief financial officer Andrew Bonfield also departing.
Mr Carr has been no stranger to big deals during a lengthy corporate career, and was chairman of utility Thames Water when the company agreed a £4.3 billion takeover by Germany's RWE in 2000.
He is currently also chairman of British Gas parent Centrica as well as a non-executive director of the Bank of England.
Investors holding 71.7 per cent of Cadbury's shares backed the takeover yesterday, although the deal triggered protests at Westminster from unions and workers at the company's Bournville plant in Birmingham.
Kraft chairman and chief executive Irene Rosenfeld said the deal "will be good for the company, good for the UK and good for British manufacturing jobs".