She returns as the head of marketing with a brief to develop a coherent plan and identify the target audience for it within client companies.
Her appointment comes three months after the IPA council endorsed the plan to make the industry more professional and improve the calibre of staff training so that agencies are better remunerated for what they do.
Hull will report to a group chaired by Jerry Hill, the chief executive of Initiative Media, which will oversee the development of the strategy.
Hamish Pringle, the IPA's director-general, said: "The plan isn't revolutionary. These are aims we've been constantly trying to achieve. What's different is that we've now given them an overt and single-minded focus."