Physical artifacts are not neutral but are increasingly recognized across the social sciences as important to structuring meaning and social interaction. Affect control theory shows promise as a framework for articulating and exploring the role of the material world in everyday life. In this study, we formalize, extend, and elaborate this line of research, instituting physical artifacts within affect control theory. We examine how physical artifacts function within affect control theory as modifiers of identities. We undertake a full-scale identity-modification study, collecting affective meaning data from 825 respondents on 58 identities, 52 physical artifacts, and 212 artifact-modified identities across a range of identities and artifact types. We empirically estimate how physical artifacts change perceptions of identities and illustrate the application of the new equations by deriving artifact-modified identities from a range of hypothetical scenarios. Using a transformation of the equations, we also simulate how people may use physical artifacts to create a desired impression when occupying different identities. Through establishing physical artifacts within affect control theory, this research raises new questions and opportunities for the theory and those interested in the design, use, and experience of physical artifacts.