The department store chain first announced McDonald would be taking up the role back in May, but a start date was not announced at the time.
Stepping into a brand new role, McDonald will be responsible for the overall profit and loss accountability in all aspects of M&S’s non-food arm, a division of the business which has been struggling in recent years while its food division continues to boom.
She will report directly to chief executive Steve Rowe.
Up until now, Rowe had been responsible for clothing, home and beauty at M&S and he will relinquish this part of his duties as chief executive once McDonald starts.
McDonald began her career as a graduate trainee at Colgate Palmolive, then moved to British Airways, where she spent 16 years. In 2006 she joined McDonald’s.