Background Cancer and its physiological and psychological effects are well defined, but how these factors impact health system navigation for people living with cancer (PLWC) is lacking.

Objective To develop a theory explaining how PLWC navigate health systems to meet their health and well-being needs.

Methods This study used multi–grounded theory to explain how PLWC navigate health systems to meet their needs. Individuals more than 6 months postdiagnosis participated in semistructured interviews. The theory was grounded with the Health Beliefs Model and Socioecological Model to generate a candidate theory.

Results Eighteen participants were interviewed (n = 12 female); the most prominent cancer type was breast (50%). The theory comprised 5 components describing how PLWC navigate health services: (1) “being on the journey” referenced a core care team and differing utilization over time; (2) “adjusting to a new identity” addressed feeling lost and isolated and a desire to be around people who have experienced cancer; (3) “assimilating knowledge” included knowledge about cancer, timing, and source of information; (4) “navigating the health system” found health-seeking attitudes and behaviors dictated whether services were accessed; and (5) “policy environment” acknowledged how policy set the context within which all theory components exist.

Conclusions The candidate theory depicts core factors influencing how PWLC navigate health and well-being services over their cancer journey and into survivorship.

Implications for Practice The theory identifies factors that influence access to healthcare, including trust and knowledge, which can form the basis of navigational initiatives and programs.