This paper presents an application of new developed meta-heuristic Geometric Mean Optimization (GMO) algorithm, which mimics geometric mean operator unique features in mathematics with combination of power loss sensitivity index (PLSI) for the problem of optimal network reconfiguration (NR), optimal distributed generation (DG) unit allocation with optimal power factor (OPF) and unity power factor (UPF), simultaneous optimal NR and allocation of DG units with considering UPF and OPF, taking into account operational constraints and three loading levels (0.5 p.u loading (light load level), 1.0 p.u loading (nominal load level) 1.6 p.u loading (heavy load level) to solve single and multi-objective functions such as maximize voltage stability index (VSI), minimize total active power loss (TAPL) and voltage deviation (VD) in distribution network (DN). The effectiveness of the proposed technique has been evaluated on IEEE 33 bus and 69-bus networks. As a result of simultaneous optimal NR and DG unit allocation with OPF, substantial improvements have been observed in terms of VSI and minimization of TAPL and VD, as compared to optimal simultaneous NR and DG unit allocation with UPF, only DG unit allocation with UPF and OPF, and only NR and base case. When multiple objectives are considered, simultaneous allocation of NR and DG units with OPF provides better results for all types of load conditions. Using the results at nominal load level for the objective of TAPL, the proposed technique was compared with the results obtained with other existing algorithms in the literature to assess its efficacy. Based on the comparison of results, it is determined that the combined technique outperforms other techniques in the literature for the goal of TAPL at a nominal load level for all cases. This proposed technique process has a good accuracy and convergence speed which makes it a good choice for simultaneous optimal NR and DG unit allocation with UPF and OPF for problem-solving for all load conditions.