In this study, we propose analytical and experimental methods to predict and detect deformation and interlaminar crack propagation in carbon fiber-reinforced plastics (CFRPs) based on electrical resistance measurement. The electromechanical behavior of CFRP was investigated from the elastic region to crack propagation. The CFRPs were subjected to tensile, three-point bending, and Mode I dual cantilever beam loads, and the signature electromechanical response was correlated to subsequent deformations and crack propagation. The self-sensing investigation was extended to different fiber combinations and electrode placement schemes to obtain customized sensitivity. The experimental results were verified through finite element analysis. In parallel, equivalent electrical circuit modelling was conducted to obtain the “resistor components” that exist in a CFRP and predict the electromechanical behavior under various mechanical loads.