Loomes has been with Diageo for 12 years. His previous roles include head of marketing on spirits and lagers in Ireland where he played an integral role in the revitalisation of the lager category with key brands including Bud, Carlsberg and Harp in 2010.
He also led the Guinness 250th celebration in 2009 in Ireland and Arthur's Day in 2010.
The move, which is effective from 1 March, follows the recent appointment of Brian Duffy to global category director for beer.
Beer is the second largest category after whisk(e)y within Diageo and Guinness is the company’s biggest global beer brand.
Duffy said, "The role will not only leverage his marketing, innovation and specific beer capability, but also call on his great leadership skills and I am confident he will lead Guinness on the next stage of its transformational journey."
This article was first published on marketingmagazine.co.uk.