Currently, the development of clean and green energy-harvesting solutions is becoming increasingly critical. Batteries have long been considered as the most traditional and efficient technology for powering electronic devices. However, they have a limited lifetime and require constant observation and replacement. To address this issue, triboelectric nanogenerator (TENG) has garnered considerable attention as a prospective sustainable power source for smart devices. Further, several approaches for improving their output performance have been investigated. Herein, we created a unique TENG based on densely packed molybdenum disulfide (MoS2) petals grown on electrospun polyacrylonitrile (PAN) fibers (MPF) using a hydrothermal technique. Designed MPF-TENG is used for mechanical energy-harvesting and smart study room touch sensor applications. The effects of pure MoS2 powder, PAN fibers, and MoS2 grown on the PAN fibers were investigated. MoS2 addition enhanced the surface charge, surface roughness, and electrical performance. The MPF-TENG had a maximum triboelectric output voltage, current, charge, and average power density of 245.3 V, 5.12 µA, 60.2 nC, and 1.75 W/m2, respectively. The MPF-TENG remained stable for more than 10,000 cycles. The MPF-TENG successfully illuminated blue LEDs, turned on a timer clock, and could be used in smart study rooms to generate energy. This study provides an effective method for improving the performance of TENG by growing MoS2 petals on PAN fibers, with promising applications in power supplies for portable electronic devices. Furthermore, the fabricated MPF-TENG was demonstrated to be a potential touch sensor for smart study rooms to save electricity.