BackgroundThere are various impacts of COVID-19 on health systems of the world. The health systems of low- and middle-income countries are less developed. Therefore, they have greater tendencies to experience challenges and vulnerabilities in COVID-19 control compared to high-income countries. It is important to contain the spread of the virus, and likewise strengthen the capacity of health systems in order for the response to be effective and swift. The experience from 2014 to 2016 Ebola outbreak in Sierra Leone served as preparation for COVID-19 outbreak. The aim of this study is to determine how control of COVID-19 outbreak in Sierra Leone was enhanced by the lessons learned from 2014 to 2016 Ebola outbreak, and health systems reform.MethodsWe used data from a qualitative case study conducted in four districts in Sierra Leone through key informant interviews, focus group discussions, document, and archive record reviews. A total of 32 key informant interviews and 14 focus group discussions were conducted. A thematic analysis was used to analyze the data, and all transcripts were coded and analyzed with the aid of ATLAS.ti 9 software program.ResultsThe six themes obtained were composed of categories that connect with each other and with codes to form networks. The analysis of the responses demonstrated that “Multisectoral Leadership and Cooperation”, “Government Collaboration among International Partners”, and “Awareness in the Community” were among the key interventions used during the control of 2014–2016 Ebola virus disease outbreak, which were applied in the control of COVID-19. An infectious disease outbreak control model was proposed based on the results obtained from the analysis of the lessons learned during the Ebola virus disease outbreak, and health systems reform.Conclusions“Multisectoral Leadership and Cooperation”, “Government Collaboration among International Partners” and “Awareness in the Community” are key strategies that enhanced the control of the COVID-19 outbreak in Sierra Leone. It is recommended that they are implemented in controlling COVID-19 pandemic or any other infectious disease outbreak. The proposed model can be used in controlling infectious disease outbreaks, especially in low- and middle-income countries. Further research is needed to validate the usefulness of these interventions in overcoming an infectious disease outbreak.