Pediatric hospital medicine (PHM) established a new model of care for hospitalized children in the United States nearly 3 decades ago. In that time, the field experienced rapid growth while distinguishing itself through contributions to medical education, quality improvement, clinical and health services research, patient safety, and health system leadership. Hospital systems have also invested in using in-house pediatricians to manage various inpatient care settings as patient acuity has accelerated. National PHM leaders advocated for board certification in 2014, and the first certification examination was administered by the American Board of Pediatrics in 2019. In this article, we describe the development of the subspecialty, including evolving definitions and responsibilities of pediatric hospitalists. Although PHM was not included in the model forecasting future pediatric subspecialties through 2040 in this supplement because of limited historical data, in this article, we consider the current and future states of the workforce in relation to children’s health needs. Expected challenges include potential alterations to residency curriculum, changes in the number of fellowship positions, expanding professional roles, concerns related to job sustainability and burnout, and closures of pediatric inpatient units in community hospitals. We simultaneously forecast growing demand in the PHM workforce arising from the increasing prevalence of children with medical complexity and increasing comanagement of hospitalized children between pediatric hospitalists and other subspecialists. As such, our forecast incorporates a degree of uncertainty and points to the need for ongoing investments in future research to monitor and evaluate the size, scope, and needs of pediatric hospitalists and the PHM workforce.