As revealed in Scotland on Sunday, the SRU has taken a minority stake in the club who are based in Washington DC.
Scottish Rugby says it is the first Tier 1 national governing body to link with a club in the newly sanctioned Major League Rugby (MLR) competition.
Murrayfield will provide a combination of financial and rugby support to Old Glory DC team and Dominic McKay, the SRU’s chief operating officer, will sit on the franchise board.
McKay is understood to have been instrumental in negotiating the deal.
The MLR season runs from February to June and will have nine franchises competing in its second season.
McKay said: “This is a very exciting moment for both Scottish Rugby and our new partners, Old Glory DC.
“We have been working with the team behind this new franchise for some time, and I’m delighted we are now in a position to announce our association and support their arrival next season into the MLR.
“The US market has long been a strategic target for us and the potential and passion for rugby will undoubtedly grow in the years to come.
“It is important we are creative and develop opportunities beyond our own borders and we are very much looking forward to growing our relationship with the team in Washington in the years to come.”