The development of the Western philosophy of ethics initiates with the Greek and progresses through the Enlightenment and Immanuel Kant, who is generally recognized as providing the kernel of the modern elements of the subject. This Kantian kernel also forms a foundation for business ethics, and it is shown here to be an optimal coordinating system for linking the ethical content of the various subjects in the business core (accounting, finance, management and marketing). For this purpose, the Kantian approach is shown to be superior to other approaches. Furthermore, the Kantian approach lends itself well to consistency with market-based economics, and particularly to leadership development of the harmonious business organization. Illustrations of how the Kantian system can coordinate the ethical content of the various business-core subjects are presented in the form of practical business duties derived from Kant’s categorical imperative.