U.S. District Court Judge Harold H. Greene has never been one to duck the tough issues.

In his role at the Justice Department in the early 1960s as one of the key authors of the Civil Rights Act, in his supervision of the reorganization and streamlining of the D.C. Court of General Sessions later in that decade, and yesterday, in his ruling on the government's proposed settlement of its antitrust suit against American Telephone & Telegraph Co., Greene has proved repeatedly his willingness to confront the powerful and force change.

At the same time, he has won a reputation for fairness that he takes pains to uphold -- as illustrated during a picnic last year given by attorneys for opposing sides in the AT&T case, when he insisted on playing for both teams in a volleyball game.

After taking over the eight-year-old AT&T case in midstream from another judge who was dying of cancer, the 58-year-old Greene criticized lawyers on both sides earlier this year for trying to "circumvent" legal procedures, and took steps to speed up the trial process to deal with the issues as promptly as possible.

And when the proposed Justice-AT&T agreement was filed last January, Greene criticized not the pact itself but the way in which the proposed settlement was filed, because the public would not have a chance to formally comment on the agreement, as is required by law.

Yesterday, Greene again flexed his muscles, showing he would not automatically endorse the landmark divestiture plan approved by AT&T and the Reagan administration last January. What's more, in so doing, Greene indicated he intended to maintain a strong oversight role over the divestiture.

In what many lawyers say was a virtually unprecedented move, Greene gave himself the power to review the settlement at any time and issue judicial orders to make sure the divestiture plan was being carried out according to his instructions. Usually, the court does not interfere with any settlement unless the Justice Department asks its help.

Additionally, communications lawyers called his 178-page decision yesterday a "tour de force," which they said showed a thorough understanding not only of the antitrust law but also of the increasingly complex telecommunications industry.

Greene has been a U.S. District judge since 1978, after 13 years with the D.C. Superior Court and Court of General Sessions.