Students' academic motivation is malleable in nature and can change over time. Variable-centered research can detect general changes in motivational variables. Recent studies have shown that learning behaviors are driven by a combination of motivations, resulting in distinct motivational profiles. Person-centered studies can detect nuanced changes in students' motivation profile memberships. Examining the nature of profile shifts could be the key to support long-term development of academic motivation. The purpose of this study was to investigate how high-school students' academic motivational profiles changed across 2 academic years and how school belongingness and achievement feedback influenced their motivation profile memberships. Latent transition analysis of responses from 1,670 high-school students revealed 6 motivational profiles: amotivated, externally regulated, balanced demotivated, moderately motivated, balanced motivated, and autonomously motivated. Pairwise logistic regression results showed that high-school students' sense of school belongingness and their prior achievement level significantly predicted their motivation profile membership in the 2nd year, controlling for their 1st-year membership. Educational Impact and Implications Statement The study identified 6 groups of high-school students who possess unique motivational characteristics, ranging from amotivated to externally regulated, balanced demotivated, moderately motivated, balanced motivated, and autonomously motivated. The results showed that the changes in high-school students' motivation were more complex than an increase or a decrease in the level of motivation. Students moved from having 1 set of motivational characteristics to another set of motivational characteristics across 2 academic years. School belongingness and prior achievement level were positively associated to motivation shifting toward more adaptive characteristics. Understanding the patterns and predictive factors of motivational change can better inform teachers and school administers to generate strategies that support students' motivation development as a whole, shifting to increasingly adaptive motivational profiles over time. As there are few longitudinal person-centered studies of motivation situated in high school settings, the current study adds to practical knowledge about the mechanism of students' motivation development at this crucial juncture in their academic career.