Scholars have long debated the effect CEOs have on firm performance, including a focus on how their effect shifts across industries, national settings, and time. Unexplored, however, is the possibility that the CEO effect might differ in publicly traded versus privately held firms. Drawing on a unique longitudinal sample of both publicly traded and large, privately held Swedish firms from 1997 to 2013, we replicate and build upon prior CEO effects studies and find that private-firm CEOs have a greater effect on firm performance, for good or for ill, than do their public firm counterparts. Our results are strengthened after controlling for industry, firm profitability, and size in a matched-pair sample. We discuss the implications and potential future research stemming from these findings.