The employee-owned retailer also announced the arrival of Denis Hennequin, who was ousted from the helm of French hotel giant Accor last year.
John Lewis chairman Sir Charlie Mayfield said Williams and Hennequin “have a wealth of experience to bring to the partnership and I very much look forward to working with them”.
Meanwhile, Financial Reporting Council chair Baroness Hogg had agreed to postpone her retirement as a non-executive at the retailer until September “to ensure a smooth transition”. Former deputy chairman David Barclay steps down from the board at the end of this month.
Sales at John Lewis grew by a “steady” 4.9 per cent to £66.4 million last week, but its Glasgow branch was its only Scottish outlet to enjoy a rise in takings.