Research Summary Although numerous studies have highlighted the negative consequences of mass incarceration, life‐course and criminal career research has largely failed to document psychological, social, and behavioral changes that occur during periods of incarceration. This oversight is particularly noteworthy in the case of individuals serving long sentences, as they spend a significant portion of the life course behind bars. The policies and programs targeting prisoners are seldom tailored to long termers and lifers, and we know little about effective interventions, or even how to measure effectiveness, for this population. By drawing on the relevant empirical research, this article underlines the importance of reorienting some research efforts and policy priorities toward individuals serving life or otherwise long prison sentences. Policy Implications During the last 20 years, the prevalence of life sentences has increased substantially in the United States. We argue that there are various benefits to developing policies that consider the challenges and issues affecting long termers and lifers. In addition to the ethical and human rights concerns associated with the treatment of this population, there are several pragmatic justifications for this argument. Long termers and lifers spend a substantial number of years in prison, but most are eventually released. These individuals can play a key role in shaping the prison community and potentially could contribute to the development of a healthier prison climate. Investment in the well‐being of individuals serving long sentences may also have diffused benefits that can extend to their families and communities. It would be advantageous for correctional authorities and policy makers to consider the potentially pivotal role of long termers and lifers in efforts to mitigate the negative consequences of incarceration.