Donald MacKinnon is widely regarded as one of the most influential post-war British philosophical theologians. The range of his published work is wide. The topics covered by his writings include (and the following list follows no particular order): the ethics of nuclear weapons, Kant's moral philosophy, Christian doctrines, the tragic vision, Marxism, metaphysics, religious language, the philosophy of history, ecclesiology, theological anthropology. (A full bibliography of MacKinnon's writings is to be found in Brian Hebblethwaite and Stewart Sutherland, eds., The Philosophical Frontiers of Christian Theology: Essays Presented to D. M. MacKinnon (Cambridge University Press, 1982), pp. 239–48. The Preface in the same volume also provides biographical details in summary form.)

MacKinnon's work is characterized by a vast erudition, and his mode of thought is profoundly interrogative (rather than affirmative). In theological matters, he refuses to take up substantive positions, and prefers instead to ‘map’ the ramifications of the espousal of such positions. This task is invariably undertaken with great subtlety and a deep respect for the complexities of the subject matter treated. The reader is always left with the impression that what matters for MacKinnon is precisely what is left unsaid, though, typically, this too is somehow indicated in his texts.