Pomroy joined in 1996 and will report to UK CEO and North West division president Jill McDonald.
The move is the latest in a number of changes to the senior management team. It comes weeks after group CEO Don Thompson stepped down after reporting a 4% fall in US sales and a 7% decline in global sales.
Thompson is set to be replaced by British born chief brand officer Steve Easterbrook.
"Paul is a strong, highly respected leader with immense knowledge of our business and a burning passion for the success of our brand," said Jill McDonald.
"He has been part of the UK executive team that has led the sustained success of the UK business over the last eight years, which gives him a strong understanding of what our customers, our people and our stakeholder community want and expect from McDonald’s. I am very much looking forward to working with Paul in this important role."
Paul Pomroy said: "I am really looking forward to the opportunities we have ahead and to build on the strong and sustained performance of McDonald’s in the UK.
"To do this we will keep listening to our customers and build greater affinity with them to make sure they enjoy great tasting food made from quality ingredients, good value and a fun experience every time they visit our restaurants."