The digital transformation of African higher education is a pivotal driver for socioeconomic development, research excellence, and global competitiveness. However, this transformation is critically constrained by chronic financial limitations, technological dependence on foreign proprietary systems, and significant infrastructural deficits. This paper presents a comprehensive analysis arguing that the strategic, institutional-wide adoption of Free and Open-Source Software (FOSS) is not merely a cost-cutting IT strategy but a fundamental pathway for African universities to achieve sustainable innovation, pedagogical relevance, and digital sovereignty. The research employs a multi-dimensional framework, examining the socio-technical, economic, and political aspects of FOSS integration. It meticulously details the profound benefits, which extend beyond direct financial savings to encompass enhanced academic freedom, robust local capacity building, and the fostering of an indigenous culture of innovation and problem-solving. The paper provides an exhaustive survey of FOSS applications across the entire university ecosystem, from learning management systems (e.g., Moodle, Chamilo) and administrative suites (e.g., LibreOffice, GNU/Linux) to specialized research tools (e.g., R, Python, QGIS) and library management systems (e.g., Koha). A significant portion of the analysis is dedicated to a critical and honest appraisal of the formidable barriers to adoption, including technical skills gaps, cultural resistance, concerns over support and maintenance, and overarching policy vacuums. In response, the paper proposes a holistic and actionable strategic framework for successful implementation, emphasizing the necessity of visionary leadership, phased deployment, substantial investment in human capital development, and the creation of collaborative consortia. The conclusion posits that FOSS adoption represents a paradigm shift moving from technological consumerism to academic and technological self-determination, enabling African universities to tailor solutions to local contexts, control their digital destinies, and ultimately emerge as central hubs of sustainable innovation for the continent's development. Keywords: open-source software, African universities, sustainable innovation, digital transformation, higher education, ICT4D, capacity building, digital sovereignty, Moodle, policy