Electroencephalogram (EEG) asymmetry has been widely studied across the lifespan, with multiple studies conducted in infancy. However, few have investigated frontal EEG asymmetry in the context of emotional-eliciting tasks, controlling for baseline to focus on an experimental episode response. The present study was designed to address this gap in research, predicting frontal EEG asymmetry response in the context of the Still Face procedure (SFP), examining mother--infant interaction quality and infant temperament attributes as potential contributors. Moderation by infant temperament was also considered. Results indicated that intensity and tone of parent--child interactions as well as Surgency/Positive Affectivity (and component scales of Approach and Activity Level) predicted frontal EEG asymmetry during SFP, controlling for baseline. Importantly, moderation was noted for Surgency/Positive Affectivity and its Approach component, reflected in significant interaction terms and follow-up simple slope tests. That is, the effect of intensity in mother--infant interactions was qualified by child overall surgency, and approach more specifically -- infants demonstrating higher levels of Surgency/Positive Affectivity and Approach in particular were protected from the right frontal EEG response to SFP noted in the context of intense concurrent exchanges with mothers.