Developing complex enterprise systems for various organisations in this world of business transformation is a challenging issue for system developers as most business needs to adapt to these changes dynamically and align their business processes, information system and technologies to the new requirements. This transformation and alignment requires a robust architecture. Unfortunately, business and information technology architectures that are supposed to support this transformation and reduce information system complexity are often disconnected, thus causing a severe constraint on enterprise agility. The Structured System Analysis and Design Methodology (SSADM) was used to analyze our findings. An archetype - architecture for enterprise and information system integration was developed based on enterprise architecture. The architecture is comprised of sub-architectures of Business and Environment, Information and Knowledge, Information System and Services, Infrastructure and Resources and Governance and Security, providing a holistic and systemic vision of the enterprise architecture framework. Prototyping was used for the progressive building of the architecture. The developed architecture was applied in an enterprise in Nigeria to authenticate its applicability and the result shows that the new architecture can successfully be used for enterprise and information system integration, business-IT alignment and information system complexity management. The architecture facilitates traceability from business strategy to business operations as well as the underlying technical design and platform deployment of information system for effective business transformation which will align IT resources with the business strategy.