The Yorkshire club announced at the end of last month that the Bahrain investment bank's 100% takeover would be completed on 21st December.
Current owner Ken Bates will stay on as chairman until the end of the current season during a transitional period before being appointed club president.
GFH Capital deputy chief executive David Haigh, who became a director at Elland Road on 21st November, will be joined on the board by Salem Patel and Hisham Alrayes of the Middle East consortium.
GFH Capital, who first entered into talks with Leeds in May, have already transferred money into the club and will be making further funds available to manager Neil Warnock, who will have the new owners' full support.
Ahead of the 11.30am press conference, Haigh told the club's official website: "We are delighted, but also honoured and proud to be the new owners of Leeds United Football Club.
"We have had over 4,000 e-mails of support from fans and we have been overwhelmed by the reaction.
"Everyone we have spoken to in the city has been fantastic, and the atmosphere on Wednesday night was incredible, and we look forward to bringing more of the same to Elland Road."
Patel said: "We're looking forward to a bright future. This is a fresh start for the football club, and we welcome fans both old and new to Elland Road."
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