Mental fatigue-a key factor in cognitive performance and well-being-varies markedly among individuals, yet personalized neurocognitive assessment methods are still emerging. To bridge this gap, we conducted an EEG-based study examining the relationship between mental fatigue dynamics and personality traits-specifically extroversion (comparing extroverts and introverts) and neuroticism (contrasting high vs. low levels)-to enable personalized fatigue profiling. To the best of authors' knowledge, this is the first study to establish such connections within this framework. Twenty-one participants completed cognitively demanding tasks (mental arithmetic and simulated job interviews) while EEG data were recorded using a wearable system. Subjective fatigue, measured post-task using the Chalder Fatigue Scale (CFS), revealed significant differences (p<0.05$) between personality groups. Objective biomarkers were derived via spectral power analysis of EEG data from key frontal, temporal, central, and posterior regions. Two-tailed ttests indicated that extroverts exhibited lower frontal fatigue, while temporal regions showed delta and theta differences for neuroticism and beta differences for extroversion. Central regions displayed spectral differences in all bands except delta and beta for extroversion, with the left central region showing significant differences across all bands for neuroticism. At the posterior region, fatigue variations were observed in all bands at the left posterior except theta band in extroversion and beta for neuroticism. Spatial brain maps further confirmed significantly lower fatigue in extroverts and low-neuroticism individuals, aligning with the subjective reports.