The former head of account management at DDB London will be responsible for the day-to-day running of the 70-strong account management department and will report to the agency's chief executive, Paul Jackson. Jackson said: "Our brief to Philippa is to build on the department's traditional position among the agency's finest.
"Account management across the industry is in an evolutionary phase and Philippa has the stature and ability to keep us at the forefront of change."
Roberts' move brings to an end her 14-year stint at DDB London, which she joined in 1991 as an account manager.
She worked across a number of high-profile accounts including Brooke Bond Food, Quaker Petfoods, British Gas and Barclaycard. Most recently, she looked after the agency's account for The Guardian.
In 1994, she was promoted to the DDB board, before taking over the role of deputy head of account management in 1997. Three years after that, she was promoted to the position of head of account management.