This paper examines 24 apartment complexes that were in the review process by the Seoul Metropolitan Government between 2013 and 2017. First, it overviews the laws governing apartment complex construction, the four major development tools, and the control mechanism known as ‘Floor Area Ratio’ (FAR). Second, it analyses the urban and architectural morphologies of the complexes, by identifying the interconnectedness of quantitative variables such as scale, density and height, and examining how these variables relate to the unit plan arrangement and the building layout in the complex. The study discovered that there was a proliferation of stereotypical unit plans and building layouts regardless of the specifics of sites and locations. This has been exacerbated by the conflict between short-term governmental policies on public housing supply and the long-term urban management plan, which has led to greater urban discontinuity and regional imbalance. The paper argues that high-density, large-scale apartment development contributes to a paradoxical combination of heterogeneity in its urban morphology and homogeneity in its architectural typology. This paper calls for the integration and coordination of the urban management plan with architectural design as the proper avenue for the establishment of a more sustainable high-density living environment in Seoul.