With Lee as managing director and Keevill and Kershaw as creative directors, the agency plans to build relationships with advertising, media and data planning agencies, rather than being "all things to all men".
The launch follows Keevill and Kershaw's departure from Craik Jones in March this year, where they were creative directors for 11 years.
Lee has worked for the Ogilvy network for 14 years, most recently in Dallas where she set up and ran an integrated Ogilvy agency. She returned to the UK in 2001 and has spent the past three years as a marketing consultant on pan-European and global accounts, including Vizzavi, Philips and Citibank.
"DM has rightly elbowed its way onto the client's top table," said Kershaw.
"What it lacks is quality thinking to match its place alongside advertising and brand consultancy."