We extend an on-the-job search framework in order to allow firms to hire workers with different skills and skills to interact with firms’ total factor productivity (TFP). Our model implies that more productive firms are larger, pay higher wages, and hire more workers at all skill levels and proportionately more at higher skill types, matching key stylized facts. We calibrate the model using five educational attainment levels as proxies for skills and estimate nonparametrically firm-skill output from the wage distributions for different educational levels. We consider two periods in time (1985 and 2009) and three counterfactual economies in which we evaluate how the wage distribution would have evolved if we kept one of the following key characteristics at its 1985’s levels: firm-skill output distribution, labor market frictions, and skill distribution. Our results indicate that 79.2 percent of the overall wage dispersion and 72.6 percent of the within-group component can be attributed to a shift in the firm-skill output distribution. Once we assume a parametric calibration of the output per skill-TFP pair, we are able to show that most of the effect of changes in the output distribution is due to an increase in the average labor productivity of college graduates and post-graduates.