The company also acknowledged Zell gave a gift to Blagojevich last year and called the former governor the day before he was arrested.
Zell has hired Anton Valukas, a former U.S. attorney who now works for the high-powered law firm Jenner & Block, as his attorney, the Chicago Tribune said in a story posted Wednesday on its Web site.
Jenner & Block has represented the company before, Tribune Co. executive vice president and general counsel Donald Liebentritt told the newspaper.
"Mr. Valukas was recommended to work on the matter because it involved a subpoena issued by the U.S. Attorney's office," Liebentritt told the newspaper in a statement.
Tribune Co. spokesmen, Valukas and Liebentritt did not immediately respond to messages left after business hours Wednesday by The Associated Press.
Zell, referred to indirectly as "Tribune Owner" in an FBI affidavit attached to the complaint against Blagojevich, made a "courtesy call" to the governor on Dec. 8, the day before the arrest, to notify him the company had just filed for bankruptcy protection, Liebentritt told the Tribune.
Zell called several elected officials that day, including Chicago Mayor Richard Daley, according to Liebentritt's statement.
"Mr. Zell's call to Mr. Blagojevich was not returned," the statement said.
Zell also gave Blagojevich a gift in 2008. Liebentritt's statement was not specific, but described it as a music box "or other specially created work of art."
Over three decades Zell has given similar gifts to "local, national and world leaders ... designed to share Mr. Zell's vision for the coming year for the investment climate and the economy," Liebentritt said.
Federal prosecutors subpoenaed documents from the Chicago Tribune's parent company in the investigation of Blagojevich's alleged attempt to get certain editorial writers fired, spokesman Gary Weitman confirmed in December.
He said at the time the company would "fully cooperate with the government in its investigation into Gov. Blagojevich and his administration."
Based on wiretaps, prosecutors alleged that Blagojevich told chief of staff John Harris, who is also charged, to threaten to withhold aid from the Illinois Finance Authority in the proposed sale of the Chicago Cubs unless the editorial writers were fired.
Tribune Co. owns the Chicago Cubs, Wrigley Field, where the Cubs play, and the Chicago Tribune.
Blagojevich is also accused of plotting to sell the U.S. Senate seat left vacant by President Barack Obama. He denies wrongdoing.