New quality productive forces are the core driving force behind high-quality economic development, and their enabling effects and mechanisms on the private economy are critical issues that urgently need clarification. Based on provincial panel data from China spanning 2013 to 2024, this study investigates the driving role and underlying logic of new quality productive forces in promoting high-quality development of the private sector. The findings reveal that new quality productive forces significantly and positively drive high-quality development of the private economy, with industrial upgrading serving as a partial mediator in this relationship. New quality productive forces primarily enable high-quality development indirectly by facilitating the transformation of the private sector toward higher-end and service-oriented industrial structures, and its driving effect exhibits significant regional heterogeneity. Going forward, it is advisable to further expand the coverage of new quality productive forces, strengthen resource allocation and technical support for central, western, and northeastern regions, implement differentiated industrial policies, enhance the endogenous momentum of private enterprises, and promote deeper integration between new quality productive forces and high-quality development of the private sector.