Maladaptive emotion regulation (ER) strategies are a transdiagnostic construct in psychopathology. ER depends on cognitive control, so brain activity associated with cognitive control, such as frontal theta and beta, may be a factor in ER. This study investigated the association of theta and beta power with positive affect and whether emotion regulation strategies explain this association. One hundred and twenty‐one undergraduate students (mean age = 20.74, SD = 5.29; 73% women) completed self‐report questionnaires, including the Emotion Regulation Questionnaire and the Positive and Negative Affect Schedule. Spectral analysis was performed on resting state frontal electroencephalogram activity that was collected for eight 1‐min periods of alternating open and closed eyes. Relative beta and theta band power were extracted relative to global field power at frontal channels. Regression analysis revealed that positive affect is significantly predicted by theta power (β = 0.24, p = .007) and beta power (β = −0.33, p < .0001). There was an indirect effect of beta power on positive affect via reappraisal, but not suppression. Additionally, theta power significantly predicted suppression, but no indirect effect was observed between theta power and positive affect. These findings are consistent with a prior study reporting a positive and negative relationship between theta and beta power, respectively, and positive affect induction. This study elucidates how modulation of theta and beta bands link to ER strategies.