Even when consumers evaluate a new product as attractive, the impact of product expectations on purchase behavior may vary depending on which self-regulation strategy is employed. This study examined how product expectations affect purchase intention when mental contrasting and indulging self-regulation strategies are primed through messages. Furthermore, the mediating effects of uncertainty, intrinsic motivation, extrinsic motivation, and energization between product expectations and purchase intention were examined. The results showed that when mental contrasting messages were provided, the effect of expectations for new products on purchase intention was greater than when indulging messages were provided. Additionally, when mental contrasting messages were provided, higher product expectations reduced uncertainty perceptions, which in turn had a positive effect on purchase intention. In contrast, when indulging messages were provided, uncertainty did not mediate the relationship between product expectations and purchase intention. Furthermore, when mental contrasting messages were provided, higher product expectations increased energization, which had a positive effect on purchase intention, whereas the mediating effect of energization did not appear when indulging messages were provided. Finally, the sequential mediating effect whereby product expectations influenced purchase intention through extrinsic motivation, intrinsic motivation, and energization in sequence was statistically significant only when mental contrasting messages were provided. Based on these findings, academic and practical implications for consumers' new product purchases were provided.