The Rotherham based firm join Eric Twigg Foods (Pukka Pies) and Ben Bennett Jnr in their financial support of the New York Stadium by penning a deal to sponsor one of the stands.
Andy Wilson, Account Director at Morrison Rotherham said to themillers.co.uk: "We are very proud to be announcing our sponsorship of the Community stand; for us it not only marks our support for this great local club but also the wider Rotherham community, which will be brought together by the stadium. Everyone at Morrison is looking forward to seeing the completed stadium and having the Millers back in Rotherham."
Steve Lewis, Head of Commercial for Rotherham United added: "Morrison is a key community partner for Rotherham United so it is fitting they have chosen to sponsor the south stand at the New York Stadium.
"They are one of several partners who have backed the Millers' community projects and their support has been pivotal to us being nominated for Community Club of the Year. Now, thanks to partners like Morrison, we can deliver our community projects from a brand new state-of-the-art stadium facility, which will continue to benefit the community.
"We are delighted to have them on board and to be extending our partnership with the company at this historic time for Rotherham United. In this new era for the club, we look forward to working together to enjoy an exciting and successful future."
The South Community Stand, which will mainly house the away support at New York, will hold 2,755 fans, a disabled seating area and have a special polycarbonate on the roof edges to allow light onto the pitch.
The deal leaves only the North 'kop' free of sponsorship with something expected to be announced in due course.
New York Stadium breakdown:
The North Kop
Eric Twigg Foods Pukka Pies Stand
Ben Bennett Jnr Family Stand
Morrison PLC Community Stand