Nowadays, replacing petroleum-based or non-biodegradable plastics with biodegradable polymers made from starch and different reinforcing materials has recently gained attention. Consequently, there is a quest to search for alternative and cheap raw materials to produce bioplastics. In this study, mucilage from Ethiopian cactus species was extracted using the microwave-assisted extraction technique, which made it possible to develop biodegradable polymers that were inexpensive, readily available, simple to make, and environmentally friendly. The effect of microwave power 300–800, solid-liquid ratio 1:5–1:25, concentration 0.1–0.8 mol/l sodium hydroxide solution, and extraction times of 2–10 minutes on mucilage were studied, and the maximum yield of mucilage was attained at optimized parameters of microwave power of 506 watts, extraction time of 9.5 minutes, solid-liquid ratio of 1:20, and 0.606 mol/L of sodium hydroxide solution. Biodegradable polymers made with mucilage have poor mechanical characteristics and are thermally unstable. Thus, to mitigate the stated problems, glycerol as a plasticizer and acid-leached kaolin crosslinked with urea as a reinforcing material were used. Moreover, the effect of acid-leached kaolin and glycerol on the physico-chemical properties of the films was studied, and a maximum tensile strength of 6.74 MPa with 18.45% elongation at break, thermally improved biodegradability of 26%, were attained at 10% acid-leached kaolin and 20% glycerol crosslinking with 2% urea. But the maximum degradability of 53.5% was attained at 30% glycerol content. The control and reinforced films were characterized using TGA, FTIR, SEM, and XRD to determine the thermal, functional group, morphology, and crystallinity of the bioplastics, respectively. These biodegradable plastics can be used for packaging non-food and dry food materials.