Behind the public rift between the management of Tribune Co. and the Chandler family that founded Times Mirror Co., a little-known person with a big impact has become a subject of intense interest and quiet controversy.

In the feud over the future of Tribune Co.'s $9.6 billion media empire, wherever there is a point of dispute between Tribune Co. management and the Chandler family, one man is somewhere nearby: Thomas Unterman.

Not a member of the family, but a masterful financial adviser to the Chandlers, Unterman has come into conflict with Tribune management time and again, several sources say. He has helped steer the Chandlers on a course that ultimately put them at odds with Tribune Co. management.

Now with the dispute between the two sides leaving Tribune Co. in the position of having its financial restructuring publicly questioned, Unterman remains in his familiar position behind the scenes. But he is again at the center of the action.

Unterman was key to bringing Tribune and the Chandlers together, resulting in the $8.3 billion acquisition of Times Mirror in 2000. The complex, tax-advantaged partnerships he created for the Chandlers helped clear the way for the sale.

Now, that same savvy financial maestro is the main behind-the-scenes adviser to the Chandlers as they challenge Tribune Co.'s $2 billion stock buyback plan.

Jeffrey Chandler, family lawyer Robert Stinehart Jr. and retired executive Roger Goodan represent the Chandler family on Tribune's board. But one source familiar with the board's thinking believes Unterman--who once sat on Tribune's board but left in a downsizing in 2001--is pushing the Chandler family's hard line on many issues.

"Unterman is the key guy in all this," said one source knowledgeable about the thinking of Tribune directors.

Unterman would not comment for this story. A spokesman said Unterman has acted properly in all respects.

Unterman's role in the current boardroom fight is bringing new scrutiny to all of his past dealings on behalf of the Chandlers.

One particular bone of contention for Tribune: Unterman's management of an investment partnership jointly owned by Tribune and the Chandlers.

After the investment fund suffered $200 million in losses during the dot-com crash in early 2000, Tribune Co. executives fumed when the Chandler family representatives to the partnership pushed through a plan that in effect forgave some of Unterman's losses.

Tribune Co. sources also question whether Unterman structured the fund's most profitable investment, in a company called Sandpiper Networks Inc., in a manner that favored the Chandler family, to the detriment of other shareholders.

Tribune sources also suggest Unterman is putting the Chandlers' desire to avoid taxes ahead of the interests of other shareholders as he urges the family to push for a restructuring or possible sale of Tribune.

A spokesman for the Chandlers said Tuesday, "Tribune management's statement that this is about taxes is just a smokescreen." The statement further said it is highly unlikely that Tribune would have to incur any tax liability.

A friend of Unterman's, former Salomon Bros. Chief Executive Robert E. Denham, said Unterman is doing what he does best: Looking after his clients' interests and creatively managing a complex situation.

"There's a sense of responsibility, and also a very interesting set of issues that he's dealing with," Denham said.

Unterman, 61, has come a long way since the days in the 1950s when he dove into the pool at Evanston Township High School as a member of the school's swim team. After obtaining a law degree at the University of Chicago, he practiced law in California before joining Times Mirror in 1992. He quickly rose to become chief financial officer.

It was at Times Mirror that Unterman developed a reputation as one of the country's most creative devisers of tax-advantaged transactions. Unterman's savvy and intimate knowledge of the structure of the Chandler family empire put him in a position to broker Tribune Co.'s landmark purchase of the California-based media empire.