A detailed extraction strategy for a compact DC drain current model parameters for GaN high-electron-mobility transistor (HEMT) devices is presented. Further, an optimization is applied on the extracted parameter values in order to get a better accuracy of the estimated parameters. The implementation of the extraction scheme can be carried out by using only a four sets of measurement data. The efficacy of the parameters extraction and optimization schemes is demonstrated by means of SPICE simulated synthetic data corresponding to two different HEMT devices, and subsequently by using experimental data for two different AlGaN/GaN HEMTs having different gate lengths. High level of model accuracy proves the utility of the proposed methodology in each case.