The Great Neck, N.Y., real estate firm said Callan was with closely held First Washington Realty. He has been on the One Liberty board since June 2002.
"With more than 18 years of in-depth real estate experience and with the knowledge of our Company that he has acquired as a director, Patrick will continue to be a great asset to One Liberty and a wonderful addition to our executive team," CEO Fredric Gould said.
The news comes two months after the company's previous chief executive, Jeffrey Fishman, quit amid
allegations of improper financial dealings. At the time, One Liberty named then-chairman Gould to the added CEO and president posts to replace Fishman. On Monday, One Liberty said Gould would give up the president's job but keep the other two.
On Monday, One Liberty rose 24 cents to $20.15.