Cardiac computed tomography (CT) has progressed from a non-invasive test primarily used to exclude obstructive coronary artery disease into a comprehensive cardiovascular imaging platform for coronary artery disease, myocardial disease, valvular heart disease, and structural heart disease. Coronary CT angiography (CCTA) is now endorsed as a first-line test in appropriately selected patients with stable chest pain or suspected chronic coronary syndromes because it can exclude obstructive disease, depict coronary atherosclerotic burden, support preventive treatment, and inform referral for invasive coronary angiography. At the same time, contemporary cardiac CT is moving beyond luminal stenosis. CT-derived fractional flow reserve and myocardial CT perfusion add a functional assessment of ischemia, whereas late iodine enhancement, CT-derived extracellular volume fraction, myocardial strain, and pericoronary fat attenuation index provide information on fibrosis, ventricular mechanics, vascular inflammation, and prognosis. Cardiac CT also has an established role in transcatheter valve therapy, left atrial appendage occlusion, and prosthetic valve assessment by providing a three-dimensional roadmap for device selection, access planning, and complication prediction. Photon-counting detector CT and artificial intelligence are further expanding the capabilities of cardiac CT through higher spatial resolution, spectral quantification, automated segmentation, quantitative plaque analysis, image reconstruction, and structured reporting. This review summarizes the evidence, technical foundations, clinical applications, and implementation challenges of contemporary cardiac CT, with an emphasis on its transition toward a decision-making platform for personalized cardiovascular care.