Former Chrysler Rescuer Will Run Olympia & York : Real estate: Gerald Greenwald takes over the property developer, which is $20 billion in debt.

Olympia & York Developments Ltd., the commercial landlord staggering under about $20 billion in debt, appointed a top Wall Street investment banker Monday to run its operations and reassure jittery lenders.

The appointment of Gerald Greenwald, one-time heir-apparent at Chrysler Corp. who helped the struggling auto maker avert collapse early last decade, was announced as Olympia & York aides conferred with banks and other creditors seeking more information about the secretive company’s financial landscape.

“Gerry Greenwald is a tremendously talented executive who played an integral role in restructuring Chrysler in the 1980s,” said Paul Reichmann, one of three multibillionaire brothers who control Olympia & York.

“His proven financial and management skills will be a great help as O&Y; continues its restructuring.”

The appointment was announced a day after the resignation of Thomas Johnson, a respected New York banker whom the Reichmanns retained to help rescue the company a few weeks ago. News accounts blamed his departure on questions of how much authority Thomas would have.

Greenwald, now an investment banker for Dillon, Read & Co. in New York, said he was impressed with the rescue team he will command, calling it “virtually a who’s who in the financial community.”