Autobiographical reasoning (ABR) is a key component of narrative identity formation and refers to the process of making sense of one's life through reflective connections between past events and the self. Although this effortful reasoning process has been linked to cognitive abilities from theoretical and developmental perspectives, few empirical studies have directly examined its association with cognitive performance in adults. Therefore, the present online study investigated which cognitive and motivational factors account for individual differences in college students' autobiographical reasoning about their challenging life periods. For this purpose, a total of 180 university students were asked to recall the most challenging period of their lives and narrate it as a coherent personal story via an online questionnaire. The narratives were coded for three dimensions of ABR: causal coherence, thematic coherence, and elaboration of interpretations. Multiple regression analyses examined the predictive power of performance-based cognitive measures (abstract thinking, analogical reasoning, cognitive reflection, and interpretative story formation) and motivational tendencies (need for cognition, need for sense-making, and need for affect). Results revealed that interpretative story formation ability, assessed through a task where participants wrote a story based on an ambiguous picture, significantly predicted all three dimensions of autobiographical reasoning. Additionally, need for cognition positively predicted causal coherence, and gender emerged as a unique predictor of elaboration of interpretations, with women providing more interpretative depth than men. These findings highlight the central role of interpretive and cognitive-motivational engagement in how individuals derive meaning from challenging life experiences, advancing our understanding of the cognitive underpinnings of narrative identity development.