In light of expanding legalization of cannabis and swelling debate about the potential risks, particularly for younger users, understanding acute cannabis effects among adolescents and emerging adults is more important than ever. Contemporary models of addiction development identify subjective drug responses as central to the developmental unfolding of drug use disorders. Despite this, surprisingly little is known about cannabis’s acute subjective effects in human youths. This research utilized ecological momentary assessment (EMA) in the natural environment to identify the typical situational context of cannabis use among 85 frequent cannabis users, ages 15–24 years (M = 19.8, SD = 2.0; 48.2% female). Study aims were to (a) characterize momentary changes in several subjective states (i.e., stimulation, sedation, tension, craving, and high) when not using, just before cannabis use, and after use, and (b) evaluate whether cannabis responses varied with cannabis use disorder (CUD) severity or across the transition from adolescence to emerging adulthood in a correlational manner. Use of cannabis produced measurable reductions in craving and tension, as well as increases in stimulation, sedation, and “high.” Participants with more CUD symptoms reported greater relief of craving and increased stimulatory response and high following use. In contrast, emerging adults reported diminished stimulatory response and high following use, relative to adolescents. Results highlight the utility of EMA for characterizing cannabis response as this behavior unfolds in daily life, during a key developmental timeframe in the pathogenesis of cannabis-use pathology.