This article examines the Federal Constitution of Malaysia through the lens of Hans Kelsen's Pure Theory of Law. It first demonstrates the utility of the Grundnorm in explaining the supremacy of the Federal Constitution within the Malaysian legal system. In particular, this article establishes that despite Malaysia's colonial past, the Federal Constitution is the Kelsenian ‘historically first constitution’ of the present Malaysian legal system because of the Kelsenian ‘revolution’ that had occurred when the Federation of Malaya attained independence from the British in 1957, as well as the absence of a Kelsenian ‘revolution’ during the formation of Malaysia in 1963. The Grundnorm of the Malaysian legal system can thus be expressed as ‘one ought to obey the prescriptions of the Federal Constitution’. However, this article also argues, using the example of the basic structure doctrine controversy in Malaysia, that while the Pure Theory succeeds in elucidating a measure of legal validity for legal norms, it fails to provide any helpful insight when a constitutional dispute relates to the content of a norm rather than the interaction between hierarchically distinct norms.