This dissertation examined executive functioning (EF) as a transdiagnostic correlate and predictor of mental and physical health. Chapter I tested the independent prediction of early adolescent depression and suicidal ideation from separate ADHD dimensions (i.e., inattention, hyperactivity) and EF, including temporally-ordered mediation by academic functioning and social problems. Participants consisted of 216 children (67% male) ages 6-9 years old with (n = 112) and without (n =104) ADHD. Follow-ups were completed approximately two and four years later. Controlling for EF, inattention positively predicted early adolescent depression whereas childhood hyperactivity and EF did not. ADHD moderated the prediction of suicidal ideation from working memory: working memory marginally positively predicted suicidal ideation for youth with ADHD at baseline. Significant mediation via academic and social functioning did not emerge. Using the same sample, Chapter II discerned configurations of EF dimensions and negative emotionality using latent profile analysis with profiles subjected to tests of predictive validity of internalizing and externalizing problems and functional outcomes approximately four years later controlling for key covariates. Four profiles that differed based on EF, but not according to negative emotionality, were identified: 1) Moderately Weak EF, 2) Average EF, 3) Weak EF, and 4) Strong EF. The four-profile solution differentially predicted early adolescent internalizing problems and social problems. Chapter III employed latent profile analysis to detect patterns of EF dimensions and neuroticism (NE) in a sample of 125 young adults age 18-25 years old. Concurrent validity with respect to internalizing and externalizing problems as well as global physical and mental health was evaluated. Four profiles optimally characterized EF and NE: 1) Weak EF + High NE, 2) Strong EF + Low NE, 3) Inconsistent EF + High NE, and 4) Inconsistent EF + Low NE. Controlling for relevant covariates, the profiles were differentially associated with internalizing and externalizing problems as well as global physical and mental health. Although EF did not predict early adolescent depression beyond inattention, these studies provide preliminarily evidence that examination of EF in combination with negative emotionality/neuroticism is a valid approach to clarify relationships among these transdiagnostic risk-factors and mental and physical health outcomes.