<p>Difficulties are still present in developing sustainable and biodegradable composites with respect to their mechanical property improvement of natural-fibre-reinforced composites. Some of the limitations that would affect the use of natural fibre-reinforced composites in structural applications have things attached to their poor mechanical properties, high moisture absorption, and non-uniform fibre characteristics. This investigation involved the reinforcement of polylactic acid with pineapple leaf fibre and hemp fibre to produce a biocomposite with improved strength and durability. The composite is fabricated from compression moulding by optimizing the process with an enhanced Taguchi approach. Fine-tuning is made on key parameters like fiber content, moulding temperature, and pressure settings prior to the maximum performance achieved. Mechanical research included tensile test, flexural strength, and impact resistance. Grey relational analysis is used to identify the most significant parameters while principal component analysis helped in reducing the complexity of data for better optimization. Simulation and validation are carried out through MATLAB so that parameters like stress distribution, fiber orientation, and multi-objective optimization could be interpreted. The results showed that with the use of pineapple leaf and hemp fiber reinforced polylactic acid (PALHF-re-PLA) composite, an increase of 73.50% in tensile strength, 60.00% in flexural strength, and 58.40% in impact resistance, with further improvement as possible, is just through fiber treatment, refinement of parameters, and computational validation to ensure repeatability and better mechanical performance.</p> Graphical abstract <p></p>