Evangelos Marinakis has completed a full takeover of Nottingham Forest and offered Mark Warburton his backing.
A Forest statement released on Thursday confirmed the deal for 100 per cent of the Championship club has gone through following months of negotiations and approval from the EFL.
Marinakis is the owner of Greek club Olympiakos, winners of the Greek title for the past seven years, and the protracted deal had been in doubt after it emerged he was facing allegations of match fixing.
He is no longer facing charges, and a statement said he and fellow consortium leader Sokratis Kominakis had passed the EFL's Owners and Directors test.
Marinakis immediately announced a series of appointments aimed at "bringing back to the glory days" to a club which won back-to-back European Cups in 1979 and 1980.
Sports lawyer Nicholas Randall has been made chairman, while Olympiakos chief executive Ioannis Vrentzos takes up the same role at Forest and sporting director Frank McParland gets a contract extension.
Warburton, appointed in March, has the full support of Marinakis, who said: "We believe that in Mark Warburton and his team the right people were selected to take the club forward by delivering the passing game the club's supporters love.
"We will provide Mark and his team with the time and support necessary to rebuild the team and create the conditions for success."
The takeover means Fawaz al Hasawi, who wanted to keep a stake in Forest, leaves after five years.
Sky sources say Marinakis has been funding Forest for several months and was involved in the decision to appoint Warburton boss.