King spent eight years at the helm of the famous British family holiday resort chain.
He will be replaced by Jon Hendry-Pickup in the summer.
King, who hails from Ireland, trained as an accountant in his native Dublin.
He was headhunted by Butlin’s parent company Bourne Leisure in the late 1980s while auditing the company.
After stints in operations and Bourne’s holidays division, he joined the board in 2002 and was appointed managing director in 2011.
Hendry-Pickup, meanwhile, joins from Prezzo after overseeing a restructure of the restaurant chain, which involved closing almost 100 of its restaurants.
A former management consultant, Hendry-Pickup has previously held financial and leadership roles with Aldi, Tesco and Travelodge.
A Bourne Leisure spokesperson said: “Dermot King has decided to step down after almost eight years as Butlin’s MD and Jon Hendry-Pickup will replace him in the summer.”
They added Bourne would not be making any further comment on the matter.
