O’Sullivan, who has served as the managing director and chair of Diageo Ireland since April 2021, will take up his new role on 1 July.
Current Diageo GB boss Nuno Teles is in turn moving on to take up the role of MD for Diageo Mexico after three years working in the UK. He previously headed up the Diageo Beer Company in the US.
Meanwhile, Louise Ryan will replace O’Sullivan as the head of Diageo Ireland.
During his time with Diageo Ireland O’Sullivan helped deliver “consistent and sustainable growth”, while he was at the forefront of last year’s announcements relating to the €100 million investment in decarbonising St. James’s Gate brewery in Dublin and the €30 million investment in the production of Guinness 0.0.
Prior to joining Diageo Ireland, O’Sullivan worked in several senior roles at Mars based around the world.
“I cannot wait to get started in Diageo’s home market of Great Britain, where some of the country’s most iconic and loved brands are at the heart of celebrations,” he said.
“After four wonderful years in Ireland, I look forward to bringing my experience to this new role and build on the incredible legacy that Nuno leaves behind.”
As Diageo GB managing director, Teles made “bold decisions to reshape the business”, including the creation of the Diageo Luxury Company to oversee the firm’s portfolio of premium brands.
“While I am excited by the opportunity ahead, I will be very sad to leave the remarkable market that is Diageo GB,” he said.
“Barry is a brilliant leader and hugely respected across the business, and I have strong confidence that Diageo GB will thrive under his leadership and continue our commitment of brilliant execution.”
Headquartered in London, Diageo owns more than 200 brands including Guinness, Johnnie Walker, Baileys, Smirnoff and Captain Morgan.
