Fraught with insecurity in recent years, lack of political and educational leaders’ adoption of sound approach to governance in the state is revealed. This manifest in serious humanitarian crises: a threat to national security and the corporate existence of the country. It is against this background that the paper within the framework of systems theory examined the relationship between leadership and security challenges in Nigeria and how it has turned Nigeria into a fragile system. The universal content analysis and qualitative research design were adopted for the study, and secondary sources of data explored to collect facts. The study unveils and traces insecurity in Nigeria to bad political and educational leadership. There is no sound execution of mutual roles by the executive, legislative and judicial arms of the government. Checks and balances as well oversight functions, including rule of law are flouted. The universities have not achieved their goal of moral and mental transformation of the graduates to desist from assisting bad political leaders as thugs. Incessant Academic Staff Union of Universities' strike action caused by bad leadership also undermines sound education. The populace and leaders alike lack knowledge of the Sustainable Development Goals (SDGs) 4 target 4.7 on promotion of non-violence and peace, world citizenship, and cultural differences acceptance, which explains sound governance approach. Based on this, the study recommended among others, revitalisation of roles of the three arms of government, reformation of educational governance, and reorientation of both leaders and the led on sound governance and SDGs prescriptions.