Pepper Hamilton has been disqualified from representing the owners and publishers of The Philadelphia Inquirer in a suit filed against the paper by union leader John J. Dougherty, a former client of Pepper Hamilton.

The Pennsylvania Superior Court disqualified the firm Tuesday in a ruling that reverses a Philadelphia trial judge’s finding that Pepper Hamilton could stay on as counsel to newspaper owner Philadelphia Newspapers LLC, now Interstate General Media, and several current and former Inquirer staff members.