- A major challenge in E-government application developments for better service delivery is inadequate security features in e-government. This results in untrustworthy websites with stunted growth so that most e-government websites are confined to an informative goal as opposed to offering services. In addition, lack on interoperability within disparate information systems reduces efficiency and effectiveness of public service delivery. These two aspects determine the usability of e-government websites to deliver an online presence that offers end to end services. The purpose of the research was to propose a model that encompasses Service-oriented governance approach in the development of e-government applications using a case of Kenya’s e-government infrastructure. The research was conducted through literature reviews, surveys of the public and ICT government employees working in e-government service delivery initiatives, and observation of key government websites. The sample frame consisted of 36 respondents of which 16 worked in e-government as ICT administrators. The results from the survey identified that inadequate security and limited usability of online services as the source of low adoption rates by citizens and users. The results also indicated that lack of technology was not the issue but the poor implementation of technology and infrastructure requirements devoid of serious security integration. The results also indicated that there is a need for information as this was the most commonly used feature on the e-government websites. Consequently, the key research question in is how interoperability and security can improve usability. Therefore, a model was derived from the research findings which formed the basis of the requirements. The SUI Model was validated to prove that e-government implementations are compliant with underlying standard specifications and how interoperability can be ensured among different implementations beyond the technical approval mechanisms currently used. The infrastructure and security components attained a progression iteration rating of between 70-80% indicative of a successful implementation. The study recommended that the government of Kenya should adopt a SUI model to address cross-border issues of authentication. Additionally, for the SUI model to efficiently and optimally work the government also needs to improve Internet Infrastructure and update its data sharing policy together with their systems usability.