The rapid rise of generative artificial intelligence (AI) is reshaping marketing by transforming how firms create content, engage customers, and drive business performance. This systematic review synthesizes over sixty empirical and theoretical studies across digital marketing, retail, and brand management to examine generative AI’s contributions to content creation, customer interaction, strategic integration, and innovation. Findings show that generative AI enhances marketing efficiency and hyper-personalization, improving engagement and operational outcomes. Yet, longitudinal evidence on sustained business impact remains limited, and ethical issues such as data privacy, algorithmic bias, and transparency are inadequately addressed within current governance frameworks. Strategic adoption also remains fragmented, with operational applications prevailing over holistic marketing alignment. The review concludes that generative AI holds transformative potential for marketing innovation but requires interdisciplinary research and robust governance to ensure responsible and value-driven implementation.