Uneven workload distributions in teams can lead to suboptimal team performance. This paper therefore describes the design of a virtual assistant that supports workload harmonization in teams by measuring workload, informing team members about their own and other team members’ workload, and supporting team members in the redistribution of workload. The virtual assistant was developed in the context of train traffic control according to the situated Cognitive Engineering (sCE) methodology, which was extended to allow for a value sensitive design process. More specifically, the values ‘insight,’ ‘helping others’ and ‘privacy’ were explicitly accounted for throughout the design of the virtual assistant. A prototype of the virtual assistant was evaluated positively in a focus group. Thereby, the contribution of the paper is twofold. First, an improvement in a human-centered development methodology—sCE with values—is described and its use is demonstrated in an actual design case. Second, a novel, positively evaluated solution for workload harmonization in teams is presented.