Mr Miller Smith will succeed Ronnie Hempel, ICI deputy chairman and chief executive, in April next year when Mr Hempel takes over as chairman from Sir Denys Henderson, who is to retire.
Mr Miller Smith, 54, will be appointed as an executive director of ICI in October.
A Glaswegian, Mr Miller Smith, a non-executive director of Midland Bank, has spent his entire career at Unilever after graduating in Medieval and Modern History at St Andrews University. He joined the Unilever board in 1989 as financial director with responsibility for investor relations, treasury and mergers and acquisitions.
Since January 1993 he has been on Unilever's foods executive overlooking profit in Southern Europe together with a responsibility for food in the Asia Pacific region and ice cream.
The City gave a positive, if guarded, welcome to the news of his appointment, as further evidence of ICI's willingness to change since the demerger in 1991 of Zeneca, the pharmaceuticals and agrochemicals company.
'At this stage of the game, when you are trying to change the company's culture, bringing in an outsider is no bad thing,' said Charles Lambert, an analyst with Smith New Court.
Sir Denys Henderson said that together Mr Hempel and Mr Miller Smith would provide 'an admirable mix of continuity and outside experience to build on ICI's strong performance since demerger'.
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