Cross-sectoral city systems integration is a necessity for Smart City Development (SCD) to provide real-time services to citizens. However, there is scant knowledge about integrating city systems, while the existing literature is replete with learnings on systems integration from private enterprises. Hence, the wisdom of Enterprise Systems Integration (ESI) can be utilised to integrate systems for SCD. Yet, there is limited knowledge on the association between these two contexts. This research aims to develop an innovative model, referred to as ‘AdaptModel’, that enables the adaption of the ESI learnings for SCD based on the differences and similarities between city and enterprise through qualitative research utilising literature analysis, semi-structured interviews, and document analysis. The findings show that the difference between cities and private enterprises from a systems integration viewpoint is in degree rather than in kind. Hence, using ESI learnings for the SCD context is valuable and informative, but it would be more complex, bureaucratic, time-consuming, and expensive. The research offers guidance in addressing the systems integration challenges associated with SCD based on interrelations between SCD and ESI; this is carried out by applying a novel approach of contextualising and modifying the ESI learnings to support cross-sectoral city systems integration.