This work analyzes the thermal degradation and mechanical properties of iron (Fe)‐containing MgAl layered double hydroxide (LDH)‐based polypropylene (PP) nanocomposite. Ternary metal (MgFeAl) LDHs were prepared using the urea hydrolysis method, and Fe was used in two different concentrations (5 and 10 mol %). Nanocomposites containing MgFeAl‐LDH and PP were prepared using the melt mixing method by a small‐scale compounder. Three different loadings of LDHs were used in PP (2.5, 5, and 7.5 wt %). Rheological properties were determined by rheometer, and flammability was studied using the limiting oxygen index (LOI) and UL94 (V and HB). Color parameters (L*, a*, b*) and opacity of PP nanocomposites were measured with a spectrophotometer. Mechanical properties were analyzed with a universal testing machine (UTM) and Charpy impact test. The thermal behavior of MgFeAl‐LDH/PP nanocomposites was studied using differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). The morphology of LDH/PP nanocomposites was analyzed with a scanning electron microscope (SEM). A decrease in melt viscosity and increase in burning rate were observed in the case of iron (Fe)‐based PP nanocomposites. A decrease in mechanical properties interpreted as increased catalytic degradation was also observed in iron (Fe)‐containing PP nanocomposites. Such types of LDH/PP nanocomposites can be useful where faster degradation or faster recycling of polymer nanocomposites is required because of environmental issues.