The smartphone can be used for two context-incongruent purposes (work-related use at home and private use at work). In order to better understand these two behaviors conceptually, we aimed to (1) identify subgroups of context-incongruent smartphone users and (2) identify differences in demographic, smartphone-related, and occupational health-related characteristics among the identified subgroups. We conducted an exploratory and data-driven latent class analysis of work-related smartphone use at home and private smartphone use at work (self-reported) in a large cross-sectional sample of Dutch fulltime employees (n = 1,544). Our analysis revealed that most employees engage in context-incongruent smartphone use and identified four smartphone user classes. Comparisons of frequent and infrequent context-incongruent smartphone users revealed several interesting insights regarding demographic (e.g., frequent users were younger, more likely to be married or in a relationship, and less likely to work from their employer’s site), smartphone-related (e.g., frequent users were more likely to be provided a smartphone by their employer, attached more importance to their work-related and private smartphone interactions, and reported higher fear of missing out), and occupational health-related (e.g., frequent users reported only slightly higher job demands, job control, and work-home interference, but at the same time lower segmentation preferences and psychological detachment) characteristics. These findings provide insight into the wide-spread occurrence of context-incongruent smartphone use and could help to develop theory on and understand the outcomes of these modern behaviors. They could also help organizations to better understand their employees’ behavior, which is a crucial first step in policy development.