Purpose -The purpose of this paper is to examine the impact of consumer sociability and service provider perceived expertise on service relationship success. Design/methodology/approach -A sample of 281 consumers in the USA, randomly selected with the assistance of a commercial list service, completed the survey. Structural equations modeling, was used to test the proposed model. Findings -The findings show that customer sociability and service provider expertise are important to relationship success. In addition, the duration of the relationship was found to be a consequence of satisfaction and a driver of social benefits, which strengthens customer commitment. Research limitations/implications -Personality traits have been previously examined in a low involvement retail setting and not found to be a significant influence on commitment. This study finds that sociability does have a significant impact on service relationship success; thus, providing support for the importance of customer traits in relationship marketing in some contexts. Practical implications -While provider characteristics are expected to influence customer commitment, this study provides evidence that at least one consumer personality trait (i.e. sociability) appears to impact commitment to a provider in high involvement services. Healthcare providers should be aware that the personality of the patient may be a driver of satisfaction with and commitment to the physician, despite the doctor's perceived level of expertise. Originality/value -This research fills a gap in the literature on the link between customer traits and service relationships in a healthcare setting. Since consumers are co-participants in service delivery, it is important to understand how their characteristics impact service relationship success.