White joins MG OMD as the broadcast director, a role that was previously part of the remit of the investment director, John McGeogh, who joined Capital Radio in January.
MG OMD originally offered McGeogh's job to Vizeum's investment director, Matt Platts, who turned it down in favour of a larger role at Vizeum.
White, who previously worked at IDK Media and DDB, joined PHD in 1995.
He spent two years running its interactive unit, PHDiQ, before returning to its television department as the broadcast director in 2002.
Adam Turner, White's deputy, will replace him as PHD's broadcast director.
MG OMD has also made a series of internal promotions. Jon Gittings has been promoted to the communication strategy director and will lead communications planning activity. Mark Gallagher, the agency's head of press, becomes the press director with a place on the agency board.
The agency is filling Gittings' group account director role by hiring the former MediaCom associate director Mark Jarrett. Simon Wilden, MG OMD's group account director on COI Communications, will take on a new role within its central unit, The Source, as the head of creative solutions.
Alison Wright, the managing director of Manning Gottlieb OMD, said: "We now have a fantastically strong team in place across all areas of the business. Jon has a fantastic track record of producing innovative campaigns that go far beyond traditional media planning and buying."