The San Francisco 49ers have increased their stake in Leeds to 37 per cent, the Premier League club have announced.
Paraag Marathe, the president of 49ers Enterprises who was already a member of the Yorkshire club's board, becomes the Whites' vice-chairman.
Leeds chairman Andrea Radrizzani said: "We are delighted to welcome further investment into our club from 49ers Enterprises and I am confident that this latest partnership will help Leeds United continue to grow and develop into the team our supporters deserve.
"I have always been open to bringing partners on this journey with me, as long as these actions can benefit the long-term strategy of the club.
"Paraag and the team at 49ers Enterprises are uniquely positioned to collaborate with myself, (chief executive) Angus Kinnear, (director of football) Victor Orta and our management team to help us achieve our goals."
The 49ers bought an initial 15 per cent stake from majority owner Radrizzani in 2018.
Radrizzani took a controlling stake in Leeds in 2017.
Marathe said: "Our 49ers Enterprises team has always shared Andrea's vision for constructing a powerful and winning club in the most competitive football league in the world, and the experience of the last three seasons has been more exhilarating than we could have ever imagined.
"The hard work and bold leadership demonstrated by Andrea and his talented team has restored Leeds United's rightful place in the Premier League and we look forward to playing an even bigger role in supporting their efforts to climb the table this year and into the future."
Leeds' announcement said Marathe would be "more involved in the decision-making process and day-to-day operations" following the increase in the 49ers' stake.