Nick Miller, managing director of Miller Brands UK, is to leave the company in September to become chief executive of London brewery Meantime.
Miller joined Miller Brands UK, the UK arm of global brewer SABMiller, in October 2005 as the new company's first sales director. He was made managing director in October 2008.
Miller said: "I am sad to be leaving a great company and team, but also very excited by my new challenge with the Meantime Brewing Co.
"I have hugely enjoyed my time at Miller Brands and am very proud of the team's success to date. I am sure that the team I leave behind will lead the organisation to even greater heights."
Hector Gorosabel, MD of SABMiller Western & Central Europe, said: "I would like to thank Nick for being instrumental in establishing Miller Brands as the leading premium beer company in the UK, and wish him every success in his new endeavour.
"We are recruiting for his successor and an announcement will be made in due course."
Meantime Brewmaster and founder Alastair Hook said h had been impressed with the way Miller had grown brands such as Peroni.
"The appointment of Nick, along with continued financial backing from shareholders, should ensure the UK craft brewing revolution starts 'shaking trees' in a more professional and perceptive manner than it has done previously.
"I have always stated the craft brewing revolution in America as my greatest influence. With Nick on board we believe we can now live that dream ourselves, right here."