Due to the development of novel technologies, there emerges a demand in the industrial sector for new materials with enhanced properties. In this context, new applications are being explored for structural composites, typically involving continuous fibers characterized by low density, high strength, and high elasticity modulus, such as carbon fibers, extensively utilized in industries such as automotive, food, aerospace, household goods, and others. However, environmental concerns are also on the rise, prompting the substitution of synthetic fibers with lignocellulosic fibers (LF) like jute fibers, sugarcane bagasse, coconut, banana, among others. The use of natural fibers instead of synthetic fibers brings about various benefits to the industrial sector. Apart from being a renewable source, LF is biodegradable and cost-effective, given their common discard and lack of market value. Within the realm of many fibers scrutinized in composite materials, one finds the fibers extracted from the açaí palm stem (FEFAPS). According to Embrapa (Brazilian Agricultural Research Corporation), Brazil stands as the leading producer, consumer, and exporter of açaí globally, with consumption primarily concentrated in the northern regions of the country. A study conducted by Embrapa indicates a 675% increase in the planted area of açaí cultivars (Euterpe oleracea) for upland regions developed through agricultural research in the past 12 years. Within this backdrop, this study aims at producing polymeric composites with polyester matrix reinforced with FEFAPS at varying weight concentrations (0, 10, 20, and 30%). Tensile tests were conducted following ASTM D3039 standards, alongside impact energy assessment via Charpy testing based on ASTM D6110-18 norms, and thermogravimetric analyses (TGA) under inert N2 atmosphere, ranging from 30°C to 600°C with a heating rate of 10°C/min. For morphological evaluation, the fracture surfaces post-tensile tests were scrutinized utilizing Scanning Electron Microscopy (SEM). The tensile test results depict a linear increase in maximum tensile strength of composites with FFSAPT addition, reaching up to 48 MPa. Regarding Charpy impact tests, a progressive rise in absorbed energy until rupture was observed, with 30% composites exhibiting growth of up to 2301% compared to pure polyester. Thermal analysis demonstrated no alteration in thermal resistance with FEFAPS inclusion, with degradation onset temperatures hovering around 300°C. Lastly, SEM micrographs exhibited weak interaction between fibers and the matrix, a characteristic trait of lignocellulosic fiber-reinforced composites. In conclusion, this study establishes the successful application of FEFAPS in polymeric composites, ushering in a new perspective for their utilization and the valorization of residues generated during açaí ice cream production, commonly employed in Brazil.