A hospitalist is a physician or care provider like a nurse practitioner who provides medical care in hospital setting. This is a generic term, rather than referring to a specific type of medical practice.
Hospitalist careers are, as the name suggests, based within the hospital system. This includes early training like residencies and internships. Type and period of training varies considerably, depending on the type of medical practice involved.
The career dynamics of hospitalist careers are strongly affected by the nature of the employment market, qualifications, experience and local conditions and places of employment. The healthcare sector as a particularly high turnover of hospital staff, including physicians and nurses. This 'nomadic' professional population has considerable job mobility, and because hierarchical progression in hospital can be very slow, moving from hospital to hospital is a pretty common practice.
Hospitalist may also move outside the hospital employment area but still work in relation to it. For example, outpatient clinics and visiting specialist positions are quite common development of a hospitalist career. Some senior hospitalists also take on advisory and consulting roles, both within hospitals and in terms of local health policy, or even state and national health policy.
If you're looking at a career as a hospitalist in any particular line of medical practice, there is one major advantage in that hospitalists obtain valuable experience in the hospital sector at a very early stage in their careers. This work can be extremely challenging in a very demanding environment, but it forms the backbone of medical practice around the world. It's fair to say that without hospitalists, there would be no health sector as we know it.