While the ITV show appeals to all ages, its key demographic is 16-34, according to both ITV and show producer Fremantle Media.
M&S is planning to promote ticket giveaways for the live shows at Wembley Arena with in-store, CRM and online activity.
An M&S spokesman said it was too early to provide details on the in-store activity and declined to reveal how many tickets were up for grabs. He said: "I wouldn't say you're likely to see cut-outs of [show judge] Gary Barlow around stores."
The partnership gives the 127-year-old retailer a presence at the live final weekend of the competition and on the fashion section of 'The X Factor' website.
When the first live show airs in October, website users will be able to access bespoke footage via an M&S-branded video player.
Steve Sharp, executive director of marketing at Marks & Spencer, said: "Styling and fashion is a crucial part of The X Factor journey – for both the contestants and the viewers. So what better partner for the nation's favourite entertainment show than the nation's favourite retailer?"
There is no agreement for judges or contestants on the show to wear M&S clothing as part of the deal. However, the M&S spokesman said it would have a "close relationship with the show's stylist".
There will be a minor broadcast element to the partnership in that all in-show competitions will have M&S on-screen branding.
Mark Rosenegk, vice president of brand partnerships UK at Fremantle Enterprises, said: "The ideas that M&S came to us with were really compelling and a great fit for 'The X Factor' brand."
The show starts tomorrow with judges Louis Walsh, Gary Barlow, Tulisa Contostavlos and Kelly Rowland.
Last year's judge, Dannii Minogue, was recently dropped from the retailer's advertising campaigns.