In the preparation of bioengineered reparative strategies for damaged or diseased tissues, the processes of biomaterial degeneration and neotissue synthesis combine to affect the developing mechanical state of multi-phase, composite engineered tissues. Here, cell-polymer constructs for engineered cartilage have been fabricated by seeding chondrocytes within three-dimensional scaffolds of biodegradable polymers. During culture, synthetic scaffolds degraded passively as the cells assembled an extracellular matrix (ECM) composed primarily of glycosaminoglycan (GAG) and collagen. During development, biochemical and biomechanical assessment of the composite (cells, ECM, and polymer scaffold) were modeled at a unit-cell level to predict their individual effect on the construct elastic properties (n = 4 samples per 7 time points). This approach employed a composite spheres, micromechanical analysis to determine bulk moduli of: 1) the cellular-ECM inclusion within the supporting scaffold structure; and 2) the cellular inclusion within its ECM. This analytical technique offers an interpretation of the constituent dynamics for cell-based tissue regeneration.