Multifunctional materials that convert mechanical and optical energy simultaneously into electrical signals can become crucial for the advancement of next-generation self-powered electronic devices. Devices such as piezoelectric nanogenerators and photodetectors harvest one kind of energy thereby limiting their versatility, adaptability, and overall efficiency for real-world applications. A material, integrated through the piezo-phototronic effect, can show enhanced response to both mechanical and optical stimuli through modulation of the interfacial band structure. Here, we demonstrate a dual-functional device based on electrospun ferroelectric P(VDF–HFP)–semiconductor MoS2 composite nanofibers that simultaneously enables piezoelectric energy harvesting and self-powered photodetection. MoS2 nanosheets, uniformly embedded in the ferroelectric P(VDF–HFP) matrix, enhance the polar β-phase of P(VDF–HFP) up to 93% and facilitate efficient charge-transfer processes aiding photodetection. The P(VDF–HFP)–MoS2 piezoelectric nanogenerator delivers a peak-to-peak open-circuit voltage, short-circuit current and power density of 200 V, 14 µA and 115 µW cm−2 respectively under a sinusoidal stress of 20 N. Concurrently, a self-powered photodetector based on the composite exhibits a responsivity, specific detectivity, an on/off current ratio, rapid photo response with a rise/decay time of ∼1.08 µA W−1, ∼3.81 × 107 Jones, ∼1.79 × 102, and 0.30/0.19 s, respectively under white light (300–800 nm) illumination. The photodetector exhibits a large piezo-phototronic effect with about 63% increase in the photocurrent under a longitudinal mechanical tensile strain of 0.11%. The results highlight a design strategy for the development of multi-stimuli responsive devices that integrate ambient light sensing with efficient energy harvesting.