Pore forming toxins are important virulence factors that enable human pathogens to invade tissues and evade immunity. The Panton-Valentine leukocidin (PVL) is associated with severe Staphylococcus aureus infections, such as necrotizing pneumonia, but its role and mode of action remain controversial. PVL primarily kills front line immune cells such as macrophages by assembling into a complex that disrupts the plasma membrane. To identify whether host factors promote PVL toxicity, we have performed whole genome CRISPR screen in human macrophage cell lines. This identified receptors that enable binding of PVL to macrophages and promote PVL activity in lung infections using humanized mice models. We further provide evidence that additional host factors determined susceptibility to PVL and thus outcomes in infections. The work supports an alternative model by which PVL kills host cells.