The relationships between alumni identity, engagement, and donations have been widely studied, but their true nature is still largely unknown due to the diverse factors suspected to contribute to donor motivations. Using the framework of organizational identity (OID) theory, this study comprehensively examined the way in which these constructs interact with each other using structural equation modeling (SEM). The alumni community of a small, selective, liberal arts college served as the population of interest. The data consisted of an alumni survey, institutional engagement information, donation records, and demographic information. The three tested models differed in how donations were measured and utilized separate outcome variables: donor status, cumulative giving, and number of gifts. The results suggested different relationship characteristics in each model, emphasizing the importance of using multiple metrics in alumni donation research. Engagement was found to significantly predict both OID and donations in every model, and its significance highlights OID theory’s deficiency in accounting for relevant post-graduation experiences. The donor status model most supported OID theory by showing the importance of identity in initial support behaviors. The other models did not support the theory and emphasized the importance of using engagement as a predictor variable. Engagement was a stronger predictor than OID for both total giving and the number of gifts. While engagement is a consistently strong predictor of donations, there is evidence of the relationship being mediated by OID. OID was not significant in predicting total giving. The models advance the understanding of the field by showing that while both engagement and identity are key to predicting donations, identity is more crucial to the initial giving decision, and engagement is key to formation of long-term giving habits and increased amounts of support.