Important linkages between daily mood and identity formation have been theorized, but have not been empirically tested as of yet. This study provided a first examination of these linkages within individuals (N = 392; 55.1% boys; Mage at T1 = 13.24, SD = 0.44) across 15 series of 5 days distributed over 5 years. Results revealed negative within-time associations of educational and relational commitment with negative mood. Negative mood was positively associated with educational in-depth exploration and educational and interpersonal reconsideration. Additionally, there were some cross-lagged effects suggesting that identity and mood mutually affect one another across days. These results contribute to the growing knowledge on how identity unfolds in everyday life by revealing important associations with daily mood.