The banking industry in Kenya plays a crucial role in financial intermediation, economic growth, and employment creation. However, many banks continue to face challenges of declining profitability, customer dissatisfaction, and workforce inefficiencies, partly attributed to inadequate leadership strategies. This paper investigates the effect of core competencies and human capital development on organizational performance at Kenya Commercial Bank (KCB), Kencom House. The study adopted a descriptive–explanatory research design, targeting 400 employees across strategic departments, from which a stratified random sample of 200 respondents was drawn. Data were collected using semistructured questionnaires and analysed using descriptive statistics, correlation, and multiple regression techniques with SPSS version 25. The findings revealed that both core competencies and human capital development significantly influenced organizational performance. Core competencies such as innovation capability, technological proficiency, service quality, and responsiveness accounted for improved financial outcomes and customer satisfaction (β = 0.327, p < 0.01). Similarly, human capital development comprising training, succession planning, knowledge sharing, and employee engagement positively contributed to productivity and operational efficiency (β = 0.251, p < 0.05). The study concludes that continuous investment in distinctive organizational capabilities and human capital enhances the performance and competitiveness of commercial banks. It recommends that KCB strengthen innovation systems, align employee development programs with strategic objectives, and institutionalize knowledge-sharing platforms to sustain superior performance in an evolving financial environment.