Customer Success Management (CSM) is an emerging B2B strategy designed to prioritize and maximize customers' value-in-use. Scholars have questioned whether CSM represents a rebranding of extant customer management practices or an evolution of customer management practices. This research investigates key differences between CSM and Relationship Marketing (RM) through a literature review of definitions and statements, and by comparing and contrasting specific tasks of CSM and RM amongst eight categories of analysis. The study found significant differences between CSM and RM, particularly around sales orientation, goals and outcomes, integration/partnership, company performance, and value. Overall, our findings offer a solid view of how CSM fits with and builds upon existing RM practice. IMPACT STATEMENT Our study marks a pioneering foray into deeply analyzing the relationship between Relationship Marketing (RM) and Customer Success Management (CSM), crucial areas reshaping business engagement strategies globally. For the first time in academia, this research sheds light on how integrating these strategies enhances customer loyalty and promotes business growth, emphasizing a customer-first approach. Across the globe, millions working in marketing, sales, customer service, customer success, and support stand to benefit from the insights on deepening the application of these principles. This paper not only navigates the theoretical intersections and practical synergies of RM and CSM but also serves as an invaluable resource for professionals seeking to elevate customer engagement and satisfaction. By broadening the academic dialogue and offering strategic guidance, our findings aim to empower businesses and individuals dedicated to fostering impactful customer relationships in today's competitive landscape.