She replaces Ben Pearman who left the frozen food company to join Häagen Dazs General Mills last month.
Jobling will report to Birds Eye managing director Anne Murphy.
Previously Jobling was marketing director at Sara Lee Household and Body Care and has held roles at Unilever including R&D, innovation and brand management roles and male grooming global brand director.
Murphy says: “Margaret brings with her an impressive track record of strategic brand development and NPD, in leading marketing teams, in delivering results and growing market share. She is an accomplished leader with a strong track record of developing talent and will be a great addition to the UK board.
Jobling is the latest Cadbury marketing director to leave the confectioner since the completion of Kraft’s hostile takeover in February.
It is not known whether Jobling will be replaced at Cadbury.
Earlier this month Tamara Minick-Scokalo, who is head of Kraft’s European confectionery business.
Ignasi Ricou, who headed up Cadbury’s European gum and candy business, is also to leave the company.
Former Cadbury chairman Roger Carr, CEO Todd Stitzer and chief financial officer Andrew Bonfield have also stepped down.
Mark Reckitt, Cadbury’s chief strategy officer left in July and Cadbury’s UK marketing chief Phil Rumbol also left to launch a creative agency with Fallon founder Laurence Green and creative director Richard Flintham.