Building long-term and close customer relationships is an ever-salient function in business-to-business organisations and, especially, in expert organisations where high levels of trust and close customer interaction are needed in the production of the services. A key account management (KAM) system, an organised way for managing key customers, can be a useful tool for this purpose. However, there are many factors to consider when implementing such a system in this context. The aim of this article is to describe the specific and challenging characteristics of KAM implementation in expert organisations. In particular, this article aims to describe the kinds of organisational capabilities required for KAM system implementation and what kind of KAM organisation is appropriate to dovetail with particular organisational characteristics. This study is based on a qualitative single-case study in an expert organisation constructing its KAM practices for the first time.