This study aimed to explore the relationship among the Big Five personality traits, emotional intelligence (EIQ), psychological capital (PsyCap), and teacher well-being (TPWB) within the context of higher education. The objective was to predict TPWB in university teachers by utilizing the Big Five personality traits and PsyCap while considering EI as a mediator. Data were collected from 708 teachers in Ethiopian higher education institutions. Participants completed the Emotional Intelligence Scale (EIS-16), Big Five Personality Inventory (BFI-10), Psychological Capital Questionnaire (PCQ-12), and Teacher Professional Well-Being Scale (TPWBS). The analysis included reliability tests, correlation analysis, validity assessment, measurement invariance, and serial mediation testing. The findings unveil a significant direct positive effect of Big Five personality traits on EIQ, PsyCap, and TPWB. Furthermore, PsyCap demonstrates a direct positive effect on TPWB. PsyCap fully mediates the relationship between the Big Five personality traits, EIQ, and TPWB, while EIQ partially mediates the relationships between the Big Five personality traits and PsyCap/TPWB, accentuating a serial mediation effect. Moreover, the personality trait of openness to experience positively predicts EIQ, PsyCap, and TPWB. Conscientiousness and agreeableness also positively predict EIQ, while extraversion directly influences PsyCap in a positive manner. However, neuroticism exerts a negative direct impact on EIQ, PsyCap, and TPWB. Additionally, emotional intelligence partially mediates the relationship between the five dimensions of the Big Five personality (openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism) and TPWB. In conclusion, PsyCap fully mediates the relationship between the Big Five personality traits, EIQ, and TPWB, while EIQ partially mediates the relationships between the Big Five personality traits and PsyCap/TPWB. These findings hold significant implications for enhancing well-being among teachers.