Inglis, who joined the retail stalwart in 2008, will continue to be responsible for marketing and customer insight but his role now incorporates end-to-end customer experience.
The move brings more marketing expertise to John Lewis' senior management team. He joins Paula Nickolds on the board, who is currently buying and brand director and is being promoted to commercial director.
A spokesman for John Lewis confirmed the marketing director role will not be replaced, with Inglis continuing to have responsibility for the function.
In addition, Andrew Murphy, retail director, takes up the newly created role of group productivity director; Mark Lewis, online director, becomes retail director and Dino Rocos, operations director, assumes additional responsibilities for the omnichannel customer.
John Lewis said the changes reflect the "rapid rate of change in retail".
Sir Charlie Mayfield, The Partnership's chairman, said: "The rapid rate of change in retail is set to continue and therefore the time is right for us to develop the thinking that will help sustain the Partnership in the next generation."
Andy Street, managing director John Lewis said: "These important changes to the John Lewis Management Board place the customer at the heart of our decision making.
"The new John Lewis Board composition will ensure we continue to lead omnichannel retailing in the UK."