Walker will succeed Norgaard, who has been with the business for 14 years, and will also retain his current role. He has taken the role of deputy CEO this month to help ensure a smooth transition.
Norgaard joined the company in 1997, following its buyout from Allied Domecq, and helped drive growth by reorientating the company from a frozen to a chilled business.
As part of the management reshuffle, Lyons sales director Jonathan Hodgson will take on responsibility for all of the UK sales activities of both Lyons and sister company Farne Salmon from November.
Lyons marketing director Paul Vita will oversee all the marketing and new product development activities of both companies.