This paper examines the theoretical framework presented in Peter Drucker’s book entitled “The Theory of Business” in conjunction with the concept of intellectual capital, to clarify the underlying rationale influencing organizational behavior, strategic formulation, and performance outcomes. Specifically, it analyzes how foundational assumptions of business theory regarding an organization’s external environment, mission, and core competencies, align and integrate with the three principal components of intellectual capital, namely: human capital, structural capital, and relational capital—the latter being also referred to as customer capital in the literature. The study further demonstrates how the synergistic interaction between these conceptual elements contributes to organizational effectiveness and competitive advantage in contemporary business environments. Its insights presented offer a conceptual basis for understanding how knowledge assets and strategic assumptions drive innovation, organizational growth, and sustainable business success in the digital economy.