This topical review assesses the growing role of cardiac biomarkers beyond cardiovascular health and focuses on their importance in stroke and dementia. The first part describes blood-based cardiac biomarkers in patients with stroke and highlights applications in the setting of early diagnosis, poststroke complications, outcome prediction as well as secondary prevention. Among other applications, natriuretic peptides can be helpful in differentiating stroke subtypes. They are also currently being investigated to guide prolonged ECG monitoring and secondary prevention in patients with stroke. Elevated cardiac troponin after ischemic stroke can provide information about various poststroke complications recently termed the stroke-heart syndrome. The second part focuses on the role of cardiac biomarkers in vascular cognitive impairment and dementia, emphasizing their association with structural brain lesions. These lesions such as silent brain infarcts and white matter hyperintensities often co-occur with cardiac disease and may be important mediators between cardiovascular disease and subsequent cognitive decline. ECG and echocardiogram measurements, in addition to blood-based biomarkers, show consistent associations with vascular brain changes and incident dementia, suggesting a role in indicating risk for cognitive decline. Together, the current evidence suggests that cardiac blood-based, electrophysiological, and imaging biomarkers can be used to better understand the heart and brain connection in the setting of not only stroke but also dementia.