Self‐regulation and self‐control of attention and impulse (emotion and behavior) are fundamental to adaptation and closely intertwined. Accordingly, disturbances in regulation of attention and impulse are ubiquitous in developmental psychopathology, but attention‐deficit/hyperactivity disorder (ADHD) comprises a paradigmatic neurodevelopmental condition for examining typical and atypical functioning and development of these abilities at multiple levels of analysis. It is described. Then a two‐process model of regulation is used as heuristic for organizing both the functioning of attention and impulse control and the related literature on ADHD pathophysiology. For both inattention and impulsivity, type 1 (bottom‐up) and type 2 (top‐down) regulatory processes, their corresponding formal measurement, and corresponding neural instantiation are described to the extent the literature allows. Impulsivity can be linked to temporal discounting of reward, here presented as a bottom‐up process that intersects particularly, but not exclusively with emotion regulation. It can also be linked with response inhibition or response suppression, here presented primarily in its top‐down aspect. However, it can also occur in a bottom‐up fashion via emotional arousal. Therefore, integration of cognition and emotion is conceptually essential for understanding self‐control, impulsivity, and inattention. Additional processes accordingly are contained with these heuristic type 1 and type 2 manifestations and are elaborated to add nuance to the general framework proposed. In each section, typical functioning is described and findings in relation to ADHD are highlighted including behavioral, neuropsychological, and neuroimaging findings. Developmental etiology is discussed in relation to molecular genetic approaches, gene by environment interplay, and epigenetic emergence of function and dysfunction. Conclusions and future directions are proposed, highlighting the emerging tractability of revised neurobiologically based nosology for ADHD, the importance of adding contextual nosology to biological nosology, and the integrative potential of an epigenetic model.