In the modern world, the disposal of wastes and its reusage is always a challenging task. Many researchers have been working toward the reusage of wastes. This research article reports on one such method to reuse the pet bottles that are used worldwide. The pet bottles were crushed, then they underwent a pyrolysis process, and the polyethylene terephthalate (PET) char extracted from it was used as reinforcement for composite production. Waste bottles are collected and chopped into small pieces and packed in a closed container. This container is kept in the furnace and maintained at a temperature of 300°C. After 3 h, the plastic char is taken from the container and ball milled for about 5 h in order to obtain the PET char in fine powder form. The extraction of PET char followed by the mechanical property studies on PET char derived from waste PET bottles has been carried out to know its effectiveness as a primary reinforcement in the polyester matrix and will be discussed in detail. The PET char is reinforced with polyester composites with varying weight percentages of 5, 10, and 15 %. The addition of PET char in the polyester matrix drastically increases the tensile strength and flexural strength by 24 and 20 % compared with pure polyester matrix. From the results, it was noted that 10 % wt. PET char-reinforced composites revealed better mechanical properties, which indicates its potentiality to be used for composite manufacturing.