ABSTRACTStaphylococcus aureusis a Gram-positive commensal and opportunistic pathogen able to cause diseases ranging from mild skin infections to life-threatening endocarditis and toxic shock syndrome. The ability to cause such an array of diseases is due to the complexS. aureusregulatory network controlling an assortment of virulence factors, including adhesins, hemolysins, proteases, and lipases. This regulatory network is controlled by both protein and RNA elements. We previously identified a novel regulatory protein called ScrA, which, when overexpressed, leads to the increased activity and expression of the SaeRS regulon. In this study, we further explore the role of ScrA and examine the consequences to the bacterial cell ofscrAgene disruption. These results demonstrate thatscrAis required for several virulence-related processes, and in many cases, the phenotypes of thescrAmutant are inverse to those observed in cells overexpressing ScrA. Interestingly, while the majority of ScrA-mediated phenotypes appear to rely on the SaeRS system, our results also indicate that ScrA may also act independently of SaeRS when regulating hemolytic activity. Finally, using a murine model of infection, we demonstrate thatscrAis required for virulence, potentially in an organ-specific manner.IMPORTANCEStaphylococcus aureusis the cause of several potentially life-threatening infections. An assortment of toxins and virulence factors allows such a wide range of infections. However, an assortment of toxins or virulence factors requires complex regulation to control expression under all of the different conditions encountered by the bacterium. Understanding the intricate web of regulatory systems allows the development of novel approaches to combatS. aureusinfections. Here, we have shown that the small protein ScrA, which was previously identified by our laboratory, influences several virulence-related functions through the SaeRS global regulatory system. These findings add ScrA to the growing list of virulence regulators inS. aureus.