This paper examines the strategic drivers of effective key account management (KAM) and their integration into the relationship lifecycle. Previous KAM initiatives have tended to be focused on the sellers' perspective, resulting in bias, resistance and subsequent failure of many KAM systems. We contribute to previous research by first, identifying a set of processes relevant to the strategic co-creation of relationship value and the role of KAM in this process. These processes include the relational co-creation of value, collaborative inter-firm communication, and joint problem solving. Secondly, we consider the moderating implications of KAM relationship lifecycle phases on the influence of these key processes. Recent research has established that relationship development transitions across phases of exploration, build-up, and maturity with variations in underlying relational dynamics across the phases. KAM systems thus need to factor in the relationship cycle when directing resources towards their key accounts.