The commercial deal means the 23-year-old German will be the face of the campaign to raise Infiniti’s brand profile and products during events and race weekends.
Vettel, who is also a brand ambassador for Tag Heuer, is likely to be in receipt of further high-profile sponsorships deals.
The move comes two months after the car manufacturer announced a major partnership with the Red Bull Racing Team for the 2011 Formula 1 season.
Vettel is a member of the Red Bull Racing Team and drives an RB7, part of the Infiniti range, as does team member Mark Webber.
Simon Sproule, chief vice-president, global marketing communications, Nissan Motor Company, said: "Red Bull Racing have demonstrated over the course of their short history in F1 that they are a great challenger brand, unafraid of taking their own approach to creating a winning team.
"At the core of this emergence has been the inspired performance of Sebastian Vettel. As we developed the partnership with the team, so it was a natural progression to also work more closely with Sebastian, and today we formally welcome him to the Infiniti team."
Red Bull extended its contract with Vettel in March, making the current F1 world champion part of the Red Bull Racing team until the end of 2014.
The global Infiniti F1 programme has been developed and managed by PRISM, the sponsorship agency.
Vettel is currently leading this year's F1 World Championship.