Prospective memory (PM) reflects the product of cognitive processes associated with the formation, retention, delayed initiation, and execution of intentions. It has been proposed that developmental changes in PM across the lifespan are heavily dependent upon the developmental trajectory of executive control functions. This study is the first to apply a complex PM task to children, young adults, and older adults. The procedure allows for the assessment of each of the 4 phases of PM. During intention execution, the authors additionally manipulated whether participants had to actively interrupt attention to the current "ongoing" task in order to switch to the execution of the next intended task. Group differences mirroring inverted U-shaped functions were observed in those phases conceptualized as relying on executive control (intention formation, initiation, and execution). Age differences in intention execution were substantially greater when active task interruption was necessary. The current study provides the first evidence of growth and decline of complex PM across the lifespan and suggests that the degree of inhibitory control needed to succeed in the task may be one factor underlying this development.