Mortality is a basic aspect of population dynamics, shaping demographic structures, fertility behaviors, and long-term growth trajectories. While demographic scholarship has extensively examined fertility transitions and migration, the role of death as a structuring force in population studies remains comparatively underdeveloped, particularly in Sub-Saharan Africa (SSA). This article empirically analyzes mortality patterns in SSA and their implications for human population growth, situating the study within demographic transition theory, epidemiological transition theory, and the framework of social determinants of health. Drawing upon secondary quantitative data from the United Nations World Population Prospects (2022 Revision), World Health Organization mortality statistics, and Demographic and Health Surveys (DHS), alongside qualitative analyses of case studies in Nigeria, Kenya, and South Africa, the study employs a mixed-methods design. Findings demonstrate a complex interplay between mortality decline, fertility patterns, and rapid population growth in SSA. Mortality has declined substantially since the 1960s, yet infant and under-five mortality remain disproportionately high compared to global averages. The analysis further reveals that mortality reduction has not translated into fertility decline at the same pace, thereby sustaining high population growth rates. Qualitative evidence illustrates cultural perceptions of death, structural inequalities, and weak health infrastructures as mediating factors in mortality outcomes. The study concludes that mortality should not be understood as merely a demographic background variable but as a central dynamic shaping the future of human population growth. Policy implications underscore the need for robust health systems, poverty reduction, and culturally sensitive interventions to accelerate the demographic transition in SSA.