The burden of health issues surrounding the children and adolescents (ChAds) population is of great concern. From metabolic disorders such as obesity, non-alcoholic fatty liver disease, diabetes, multiple sclerosis including mental and several other psychological disorders like attention deficit hyperactivity, internet addiction, autism spectrum, subthreshold mood symptoms and depression, and stress disorders, is a nexus of the gut microbiota (GM) profile and physical activity (PA), as they both play a crucial role in ameliorating these disorders. The aim of this review is to explore the disorders with regard to their association with ChAds’ GM and its health. We started with brief descriptions of PA and its connections with GM profile cum health in ChAds. In addition, the disorders in ChAds were broadly classified into metabolic and psychological. Observations from the discussed sections show that exercise and physical activity are efficient methods for enhancing physical, metabolic, and mental health, which are often GM-mediated, and thus might require certain levels of personalization. Furthermore, age, gender, genetics, baseline BMI, baseline exercise level, and diet are key parameters to be explored when proffering intervention of combative mechanisms against these disorders.