Recently a variety of advanced PLL methods have been proposed for single phase grid connected applications. For such applications, the correct generation of reference signals is of the utmost importance. To ensure this, an accurate and fast estimation of the phase angle and the frequency of the utility voltage is essential. Among the methods proposed to achieve this, the Park PLL is the most commonly utilized method due to its simple design, low computational load, and optimal performance under distorted grid conditions. Despite the wide acceptance and usage of this method, there hasn't been a definitive method to fine tune and optimize its parameters reported yet. In this paper an improved Park based PLL is proposed which utilizes genetic algorithm in order to fine tune these parameters, which guarantees a fast response and a robust performance. The key point to implement this PLL is to generate the orthogonal signal accurately and quicker, even under distorted grids which may consist of harmonics, noise and DC components. Finally, the response of the proposed PLL has been evaluated using MATLAB and its results are presented to support the theoretical analysis. © 2016 IEEE.