Five studies examined whether quality of motivation (as individual differences and primed) facilitates or thwarts integration of positive and negative past identities. Specifically, more autonomously motivated participants felt closer to, and were more accepting of, both negative and positive past characteristics and central life events, whereas more control-motivated participants were closer to and more accepting of positive, but not negative, past characteristics and events. Notably, controlled motivation hindered participants' acceptance of their own negative identities but not of others' negative identities, suggesting that control-motivated individuals' rejection of negative past identities was an attempt to distance from undesirable parts of themselves. Defensive processes, reflected in nonpersonal pronouns and escape motives, mediated interaction effects, indicating that lower defense allowed fuller integration. Integration of both positive and negative past identities predicted indicators of well-being, namely, vitality, meaning, and relatedness satisfaction.