In this Paper, an estimator of the alpha-kappa-mu distribution, based on the maximum likelihood (ML) estimation method, is proposed and verified. The technique is applied in samples generated by the Smith spectrum method, which is also a contribution in this paper. This distribution has been recently proposed to model the received field strength in a non-linear environment with line-of-sight condition. Hence, efficient estimators are required to infer the parameters of the received signal amplitude distribution in propagation mediums modeled by it. The ML estimator for the alpha-kappa-mu distribution is derived and verified against chosen true values of the parameters by means of a simulation. We verify that, for a large sample size, the estimators are unbiased, from a practical point of view, for the useful range of alpha, kappa, and mu. The results conclude that the estimator variations about its sample mean are smaller for the a parameter.