Holliday-Williams, formerly a managing director and member of the executive committee of Direct Line Group, will join the firm on 1 October ahead of Grace stepping down in March following ten years with the business.
Alex Wynaendts, chief executive of Aegon UK’s Dutch parent group, said: “Mike’s appointment signals Aegon’s continuing commitment to build on the strong foundation of our UK business.
“Mike brings extensive experience in the financial industry and a strong track record in focusing on customer solutions. I look forward to working with him.
“We would like to thank Adrian for having successfully modernised, transformed and repositioned our UK business.
“Under his leadership, our UK business has grown from £40 billion of unit-linked pensions in 2009, to today where we oversee £175bn of pension and investment assets.
“We have repositioned Aegon to be the leader in the market of investment trading platforms and the company is now well positioned for further growth. We wish Adrian well in his deserved retirement.”
Holliday-Williams added: “I look forward to working with advisers to develop new solutions to enhance their relationships with their clients.”
Grace, who will retire from the firm on 31 March, said he would work with his successor to ensure a smooth transition.
Last month, Aegon UK hailed a “milestone” as assets on its platform exceeded £140bn for the first time, up from £128bn at the start of the year. Grace said Aegon UK had delivered a record £160 million dividend to its Dutch parent. Total assets administered on behalf of customers hit £173bn.