To date, the discussion regarding corporate social responsibility (CSR) has primarily addressed organizational rationale and activities. Little has been said about the individual characteristics and behaviors that promote the development of CSR within organizations. In this paper, we propose and test a model to explain individual differences in the propensity to engage in socially responsible behavior (SRB). By linking values, affect and reasoning to managers' propensity to `do good' and `do no harm,' we provide a more complete picture of how SRB arises in organizations. A survey of 643 middle managers in five multinational corporations supports our contention that values, affect and reasoning matter for SRB. In particular, self-transcendence values (universalism and benevolence) and positive affect increase the propensity to engage in SRB, as do moral and reputation-based reasoning styles. Moreover, we find that values and affect shape more controlled processes such as moral reasoning. We develop implications for the interaction between the individual and the organization in promoting SRB