Hagg joins the company in this newly created role and will report directly to recently appointed corporate affairs director, Toby Nicol.
Formerly head of social policy at British Gas, Hagg helped to reposition the company on fuel poverty and energy efficiency. He also previously worked as issues manager at Shell UK, where his remit included climate change and human rights.
Hagg also previously worked at communications consultancies Luther Pendragon, Consolidated PR and Hill & Knowlton where he established its CSR practice.
He will be responsible for ensuring sustainability remains at the core of all Findus Group activity.
Hagg is also chairman of the Climate Clinic, a coalition that brings together the country's major environmental groups at party conferences.