Corporate social responsibility can improve firms’ ability to recruit highly motivated employees. This can secure socially responsible firms’ survival even in a highly competitive environment. We show that if both socially responsible (green) and non-responsible (brown) firms exist in equilibrium, workers with high moral motivation, who shirk less than others, will self-select into the green firms. If unobservable effort is sufficiently important for firm productivity, this can drive every brown firm out of business—even in the case where many workers have no moral motivation whatsoever.