The field of cardiac tissue engineering has made significant strides in therapeutic and pharmaceutical applications, highlighted by the development of smart biomaterials. Scaffolds with appropriate properties mimicking the nature of a heart matrix will be highly beneficial for cardiac tissue engineering. In this study, high-aspect-ratio water-dispersed gold nanowires (AuNWs) were synthesized and incorporated into gelatin methacrylate (GelMA) hydrogels, demonstrating enhanced electrical conductivity and mechanical properties of the biomaterial scaffolds. Cardiac cells cultured on GelMA-AuNW hybrid hydrogels exhibited better biological activities such as cell viability and maturation state compared to those cultured on GelMA hydrogels. Moreover, cardiomyocytes showed synchronous beating activity and a faster spontaneous beating rate on GelMA-AuNW hybrid hydrogels. Our strategy of integrating high-aspect-ratio water-dispersed gold nanowires within gelatin methacrylate hydrogels provides a favorable biomaterial scaffold to construct functional cardiac tissue for further applications in cardiac tissue engineering and drug screening.