Within Western culture, emphasis is placed on youthfulness, thinness, and muscularity, and dissatisfaction with one’s weight is rendered normative, with maladaptive dieting and physical activity often sought to change body shape and size. Missing from the existing psychological literature on physical activity is an examination of how experiences with weight and movement are affectively laden, embodied, shaped by complex intersecting identities, and constrained by the backdrop of ageism, cis-heterosexism, racism, healthism, and fatphobia. Drawing on data from six studies exploring experiences of the body and physical activity in elite athletes, pregnant women, and older adults, we examined how individuals from diverse social positions storied their experiences with weight across the life course. Three narrative themes were identified across the participants’ stories via thematic and structural narrative analyses of semi-structured and life history interviews with 112 participants. Participants positioned fatness as a moral transgression stemming from failed personal responsibility for physical activity engagement. Participants described ‘feeling fat’, and attempted to discipline their bodies when experiencing age, pregnancy, and sport-related body changes, which engendered shame and guilt, and constrained pleasurable experiences with physical activity. Weight-related beliefs were underpinned by ageism and cis-heterosexism; participants pointed to the value of attempting to retain a thin and youthful physique through physical activity engagement to attract the opposite sex and gender. These findings contribute to the existing literature on the body and physical activity by pointing to the importance of identities and the affective and culturally imbued dimensions of weight when studying physical (in)activity participation.