Objective: to understand care management in Primary Health Care based on the meanings attributed by workers who work in this context and build a theoretical-explanatory model. Method: this is a qualitative research based on the Grounded Theory on Constructivist Data, developed in the Primary Health Care network of a municipality located in southern Brazil. Participants were selected inductively according to theoretical sampling, totaling 37 workers, divided into four sample groups. Data collection through semi-structured interviews, from January 2017 to November 2018. Data analysis took place in two phases: initial coding and focused coding. The initial codes were classified, synthesized and integrated for the development of the categories, which, articulated, gave rise to the model. To support the analysis, Nvivo®11 was used. Results: the central phenomenon “Managing care in Primary Health Care” was supported by four categories: “Organizing care management”, “Implementing care management in the care environment”, “Relating with other subjects for care management”; “Articulated socially and politically”. These categories composed the theoretical model supported by the constitution of four interdependent dimensions: organizational, relational, care and sociopolitical. Conclusion: care management, implemented in daily work, reveals itself in a variety of practices, conditions and situations that integrate the intertwined world of work and the lives of users and workers of healthcare services. The model helps those involved in care management in Primary Health Care to expand and strengthen care practices committed to users.