Physically active video games (i.e., exergames), which are a prevalent and popular childhood activity, may have benefits to executive-functioning (EF) skills, as they incorporate both cognitive engagement and physical activity. Acute EF change in 147 7- to 12-year-olds was assessed after participation in a 20-min activity. The between-subjects design had 4 conditions: exergame, sedentary video game, exercise, and nonplaying control. The varied level of physical and cognitive engagement examined whether the nature of the activity, such as physical movement or cognitive engagement in an enjoyable activity, differentially related to changes in different aspects of EF. Participants in the cognitively engaging conditions (i.e., the 2 video game conditions) improved their accuracy on the most complex EF test and their reaction time on the standard EF test more than participants in the other conditions. These findings suggest that the kind of cognitive engagement involved in video game play is the mechanism of acute effects on EF.