The move marks a return to agency life for Barton, who joined Unilever earlier this year as a customer relationship marketing consultant on a short-term contract. He will have equal equity with the other partners at Keevil Barton Kershaw.
Barton replaces Lisa Lee, who quit in September to take up a global planning role on Citibank and Vodafone at Harrison Troughton Wunderman. Lee will also handle new business at HTW. She left just ten months after helping to found Keevil Lee Kershaw.
The agency reaches its first anniversary this month, but has yet to win a major retained domestic account. Its client list includes Standard Chartered Bank (Singapore), the Commission for Architecture and the Built Environment, the legal publisher Sweet & Maxwell and the management consultancy Libra Europe.
Barton's most recent agency role was as the chief executive of DLKW Dialogue.
He quit the agency after six months following differences with its chairman, Simon Andrews. He previously worked at the creative shop Leonardo with Gary Sharpen, who is now the creative director at Red Cell Response. However, both quit when the agency was folded into Arc.
Barton was also a founding member of Jones Mason Barton Antenan, which has since been merged into Claydon Heeley Jones Mason.
Kershaw said: "Steve's arrival is indicative of our ambition as an independent. He's one of the industry's few genuine heavy-hitters."