The grand vizier Köprülü Mehmed Pasha (d. 1661) stands out as one of the most celebrated figures of Ottoman history, but despite his prominence, the basic contours of his earlier life remain largely unknown, and most of what is known derives from narrative accounts produced long after his death. This study utilizes archival sources to reconstruct Köprülü's career prior to his 1656 promotion to the grand vizierate. It reveals a major gap in the narrative sources: in 1653, when Köprülü is supposed to have been politically inactive, he was actually serving as a provincial governor in the sensitive region of Karaman in south-central Anatolia. At that time, a rebel faction was active in the area, and evidence indicates that Köprülü aligned with them. Elements of this faction, under Abaza Hasan's leadership, would later go on to rebel against Köprülü himself in 1658. Köprülü's ties to this rebel faction stand in sharp contrast to his later historical image as a paragon of order and central authority. An understanding of this period thus permits a reevaluation not only of Köprülü's political character, but also of how his supporters worked to construct his image in the aftermath of Abaza Hasan's rebellion.