This study investigates how psychological characteristics influence saving behavior within a sample of 1,380 U.S. preretirees aged 50–70 from the Health and Retirement Study (HRS). Using the 3M Model of Motivation and Personality as a theoretical basis, structural equation model results revealed that financial self-efficacy (FSE) directly explains saving behavior and is central to understanding the link between other psychological characteristics and the saving behavior of older adults. Through higher FSE, increased positive affect and reduced negative affect indirectly supported saving behavior. Moreover, the results revealed personality traits indirectly explained saving behavior. Conscientiousness and extroversion indirectly supported saving behavior; whereas openness to experience and neuroticism indirectly undermined saving behavior. This study connects broad personality traits with saving behavior, which provides information about how older adults' psychological composition is related to their saving practices.