The current study assessed whether the proportion of childhood (age 0-9 years) in poverty altered the developmental trajectories (ages 9-24) of multimethodological indicators of psychological well-being. In addition, we tested whether exposure to cumulative risk over time mediated the association between poverty exposure and psychological well-being. Measures of psychological well-being included internalizing and externalizing symptoms, a behavioral index of learned helplessness (task persistence), and chronic physiological stress (allostatic load). Exposure to poverty during childhood predicted the trajectory of each development outcome: individuals with more poverty exposure during childhood showed (a) relatively high levels of internalizing symptoms that diminished more slowly with maturation, (b) relatively high levels of externalizing symptoms that increased faster over time, (c) less task persistence indicative of greater learned helplessness, and (d) higher levels of chronic physiological stress which increased faster over time relative to persons with less childhood poverty exposure. Trajectories of cumulative risk exposure from physical and psychosocial surroundings from 9-24 years accounted for the association between childhood poverty and the growth curves of internalizing and externalizing symptoms but not for learned helplessness or chronic physiological stress. Additional sensitivity analyses indicate that early childhood disadvantage is particularly problematic for each outcome, except for internalizing symptoms which seem sensitive to the combination of early and lifetime poverty exposure. We also explored whether domains of cumulative risk as well as two alternatives, maternal sensitivity or family cohesion, functioned as mediators. Little evidence emerged for any of these alternative mediating constructs.