This study addressed the ill-understood issue of how loyalty develops in service patrons. Although many theorists hold commitment to be an essential part of this process, the link between commitment and loyalty has received little empirical attention. To address this void, the study first portrayed commitment’s root tendency to resist changing preference as a function of three antecedent processes. Second, this portrayal formed the basis for developing a psychometrically sound scale to measure the construct of commitment. Third, the scale was then used in a mediating effects model (M-E-M) to test the commitment-loyalty link. Path analyses found this parsimonious structure to be a significant improvement over rival direct effects models (D-E-Ms). Results found the tendency to resist changing preference to be a key precursor to loyalty, largely explained by a patron’s willingness to identify with a brand. Implications of these findings for loyalty’s development and research are explored.