The normal cardiac function relies on highly specialized subcellular architectures. The subcellular domains junctional membrane complexes (JMCs) are essential for excitation-contraction coupling of the myocardium. Junctophilin-2 (JPH2) has been widely recognized as the crucial structural protein involved in JMCs. Initial studies limited the role of JPH2 to anchoring junctional sarcoplasmic reticulum (SR) and transverse-tubule (T-tubule) membrane invaginations. Recently, researchers have found an expanded role of JPH2 in the development of postnatal T-tubule in mammals, progression of disease in failing hearts, hypertrophic cardiomyopathy and arrhythmias. In this review we summarized the role of JPH2 in the above physiological or pathophysiological processes and discussed the perspective in future investigation.