The combination of high-performance thermoplastic poly(ether ether ketone) (PEEK) with inorganic fullerene-like tungsten disulfide (IF-WS2) nanoparticles offers an attractive way to combine the merits of organic and inorganic materials into novel polymer nanocomposite materials. Here, we report the processing of novel PEEK/IF-WS2 nanocomposites, which overcome the nanoparticle agglomerate formation and provide PEEK-particle interactions. The IF-WS2 nanoparticles do not require exfoliation or modification, making it possible to obtain stronger, lighter materials without the complexity and processing cost associated with these treatments. The nanocomposites were fabricated by melt blending, after a predispersion step based on ball milling and mechanical treatments in organic solvent, which leads to the dispersion of individually IF-WS2 nanoparticles in the PEEK matrix as confirmed by scanning electron microscopy. In order to determine the performance of the PEEK/IF-WS2 nanocomposites for potential critical applications, particularly for the aircraft industry, we have extensively investigated these materials with a wide range of structural, thermal, and mechanical techniques using time-resolved synchrotron X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, dynamic-mechanical analysis, and tensile and impact tests as well as thermal measurements. Modulus, tensile strengh, thermal stability, and thermal conductivity of PEEK exhibited remarkable improvement with the addition of IF-WS2.