Ward takes responsibility for the London operation including brands, healthcare, corporate and B2B divisions.
She will jointly manage the company with MD Brian Beech, who runs the agency's Manchester and Edinburgh operations.
'The appointment is of strategic importance designed to generate further growth in the London agency', said Graham Lancaster, who remains CEO and chairman.
'Our board is looking to accelerate areas of growth for the agency as a whole, including digital and healthcare as well as building on the existing growth in cross-working between London and Manchester & Edinburgh, and with our colleagues in Euro RSCG Apex Communications, the ad agency and other group businesses', he said.
Ward has headed up Biss Lancaster's brands and healthcare divisions for the past two years.