Piezoelectric (PZT) materials have become popular for harvesting vibrational energy because they can replace the batteries in low-power sensors and electronic systems to increase the life span of the devices. A unimorph piezoelectric vibration energy harvester model is considered in our study, in which the substrate beam is made of laminated composite material. By considering the enhancement of the harvester design, a multi-objective optimization is carried out. The strain and fundamental frequency of the harvester are the objective, and the ply orientation and the lamina thickness are assigned as the design variables for the optimization. Using finite element analysis, the numerical analysis is carried out. From the Multi-Objective Genetic Algorithm (MOGA), the optimal design points for the ply orientation and thickness are obtained. Through finite element analysis, the optimal load resistance is calculated and the corresponding voltage output is obtained. It is observed from the study that the designed harvester model using optimal design points can produce more voltage in a low operating frequency (less than 100 Hz) environment without adding any tip mass.