Leventhal will take up the WPP agency role, reporting to MD Michael Frohlich, on 3 November.
Field has been a managing director at MHP for over four years and was previously a board director at Four Communications.
At Eulogy! she wil also be responsible for the agency’s Indian operation.
Frohlich said: "I am thrilled to welcome Lara to the Ogilvy team. Her knowledge, experience and reputation are the perfect fit for Ogilvy Public Relations/London as we move into a new era of growth."
Adrian Brady, chief executive of Eulogy, said: "We are thrilled to have someone of Lis's calibre join our team. Her big brand experience across consumer, corporate and social is exactly what our clients need."