<p>Humans rapidly and efficiently categorize others with limited information, forming split-second impressions. Prior EEG person perception research has often focused on social categories derived from perceptual cues. However, impressions are frequently based on knowledge of someone. Little research has examined how person knowledge (or the interaction between perceptual category cues and person knowledge) influences the temporal unfolding of person perception, thereby missing a common experience of everyday encounters in which individuals have access to both. Using EEG, this study (<i>n</i> = 29) examined evoked event-related brain potentials (ERPs) and functional neural network responses previously associated with changes in attention and evaluation when perceivers categorized faces based on perceived race (i.e., Black or White) or ascribed socioeconomic status (i.e., high or low). Our findings indicate dissociations between ERPs and functional network dynamics during impression formation. Specifically, in immediate response to a face, perceived race&#xa0;shaped ERPs often associated with attention (P200) and motivation/evaluation (P300). However, ascribed status influenced coordination of the neural networks underlying attention/executive functions and social cognition/evaluation throughout the categorization task, suggesting that participants attended to and evaluated status in a sustained manner. Therefore, while race perception influenced ERPs, status did not. This was the opposite for the network analyses. These findings indicate that perceptual information (perceived race) and person knowledge (ascribed status) can influence impression formation in distinct ways: one in an immediate, evoked manner, and the other through the sustained coordination of functional networks.</p>