Clift left the consumer goods company in February after almost 30 years.
He was Unilever’s first CMO and was responsible for the marketing of brands including Dove and Lynx.
Unilever appointed head of global homecare, oral care and water Keith Weed to replace Clift as CMO in March. The role has been expanded to include communications.
Commenting on the appointment, Peter Scott, chairman and joint chief executive of Engine says Clift’s “experience and knowledge speak for themselves”.
“His input will be invaluable as we continue our drive for international expansion,” he adds.
Engine describes itself as an “independent and integrated” marketing communications company. Agencies include WCRS, Dave, Partners Andrews Aldridge and Fuel.
Clients include Coca-Cola, the Central Office of Information, Vodafone, Aviva, Sky, Nike and Diageo.
As Unilever’s first ever global Chief Marketing Officer Clift, 52, controlled a marketing budget of more than £4 billion. He delivered successful global, integrated campaigns for some of the world’s best known brands, including Dove, Persil and Lynx and led Unilever to embrace the digital age.
Clift said: “Nobody involved in the communications industry could have missed the exciting development of Engine in recent years. It represents a 21st century solution to an ever more complex and fragmented media market place.
“I have known Engine for several years and have met and worked with members of the team at every level. I am particularly impressed by the high calibre of talent across the company, the collective ambition of the business and the unique position it occupies in the market.
“The changing communications landscape is a topic close to my heart, as anyone who knows me is aware. I am excited about working with a company that relishes the challenges such change brings.”
Peter Scott, Chairman and Joint Chief Executive of Engine said: “Simon’s global experience and knowledge speak for themselves. He has had a stunningly successful career as one of the most innovative and dynamic marketers of his generation and is the perfect fit for Engine. His input will be invaluable as we continue our drive for international expansion.”