<p>Stud connectors are widely used to realize the shear connection of steel girders and prefabricated bridge decks in prefabricated steel–concrete composite beams. However, the dense arrangement of stud connectors in the combined bending and shear region makes fabricating prefabricated bridge decks difficult and weakens their integrity. Therefore, a novel prefabricated steel–concrete connector (PSCC) is proposed to accelerate the prefabrication and construction of prefabricated steel–concrete composite bridges. To validate the mechanical properties of PSCC connectors, four groups of 11 static push-out specimens were tested to analyze the effect of interfacial defects and different concrete materials for the shear performance of PSCC connectors. The PSCC connectors have high shear stiffness and ductility. At load levels up to 0.9Pu, the slip values of PSCC connectors range from 6.74 mm to 11.72 mm, which specifies a minimum slip of 6 mm (EC4). The shear capacity of the specimens with 30% and 60% interface defect areas decreased by 0.39% and 8.91%, respectively, compared to the specimens with no interface defects. When the connection layer material was replaced from ordinary concrete to UHPC, the shear capacity of PSCC connectors increased by 39%, and the failure mode shifted from shear failure of studs to shear failure of reinforcements. Moreover, cyclic loading marginally enhanced the shear capacity of PSCC connectors, serving as a safety reserve in practical engineering. Finally, a shear capacity calculation formula for PSCC connectors, derived from finite element analysis and existing formulas, achieved a prediction accuracy within 6.2%.</p>