Understanding the neurocognitive basis of cognitive control and its relationship with general cognitive ability is a key challenge in individual differences research. This study investigates midfrontal theta connectivity as a neurocognitive marker for individual differences in cognitive control. Using electroencephalography, we examined midfrontal global theta connectivity across three distinct cognitive control tasks in 148 participants. Our findings reveal that midfrontal theta connectivity can be modeled as a trait-like latent variable, indicating its consistency across tasks and stability over time. However, the reliability of the observed measures was found to be low to moderate, suggesting substantial measurement error. We also replicated previous results, finding a strong correlation (r = 0.64) between midfrontal theta connectivity and cognitive abilities, especially during higher order stages of information processing. We disentangled the specific cognitive processes contributing to this relationship by employing a task-cueing paradigm with distinct cue and target intervals. The results indicated that only theta connectivity during response-related processes, not during cue-evoked task-set reconfiguration, correlated with cognitive abilities. These insights significantly advance theoretical models of intelligence, highlighting the critical role of specific aspects of cognitive control in cognitive abilities. (PsycInfo Database Record (c) 2025 APA, all rights reserved).