Juliet Peterson will take up the role from September 1.
Mark O’Malley will take the CFO role and Anthony Wesney will step into the newly created position of director of transformation.
Neal Barclay to step down next June, CFO Mike Roan to step up.
Graham Le Gros will remain with the organisation as deputy chair.
Mark Schollum will join the company in March 2025.
Nick Chapman announced amid firm-wide promotions.
Dame Paula Rebstock will be chair; Paul Reid, deputy chair; and Brodie Stevens and Linley Wood will be new directors.
Stephanie Creasy will be chief technology officer, and an internal promotion sees Renee Kinloch take the chief financial officer role.
Mark Ryland has been CEO and director of Milford Asset Management for the past six years.
Sarah Russell beat more than 200 global applicants for the job.