Conductive-filler-reinforced polymer nanocomposite (CPN) has become increasingly popular because of the combined flexibility and low cost of the polymer paired with the enhanced electrical and mechanical properties of the conductive nano-filler. The presence of a conductive filler network is reconfigurable by applied strain. It can be used in sensors such as strain gauges (for example, force sensors, pressure sensors). This research seeks to identify the underlying mechanisms that govern the electrical and mechanical properties of CPN, both theoretically and experimentally. The study theoretically elucidates the electrical conductivity and experimentally demonstrates piezo-resistivity of CPN based on phase morphological structure as well as types of polymers and conductive fillers. Experiments with controlled processing conditions and material compositions of popular polymers and conductive fillers were conducted. Comparisons were made between the experimental and simulation results of nanocomposites electrical conductivity. Consequently, adjustments were made to the simulation model until the experimental outcomes agreed satisfactorily with the simulation results. The selected fabricated samples are characterized in terms of their electrical conductivity and piezo-resistivity. Experimental results showed that the materials developed possess enhanced conductive networks and can be applied in the biomedical field where flexible non-invasive sensors can be worn outside the body to monitor vitals such as heart rate and movement.