Cell fate modification is a critical step in preparing cells and tissues for implantation therapeutics. Novel materials possessing physical, mechanical, and chemical properties similar to those found in vivo provide a potential platform in building artificial microenvironments for therapeutic applications and well-defined biointerfaces for examining differentiation potential in stem cell biology. Poly(glycerol sebacate) (PGS), a novel biocompatible and biodegradable elastomer is one such material. With tunable mechanical properties in the range of common soft tissue, the material provides an invaluable alternative platform for use in cell-to-substrate interaction studies. This paper describes the tunability of PGS mechanical properties based on variations in curing temperatures (130, 140, and 165 °C). We characterized the material by examining properties that include equilibrium Young's modulus (E), glass transition temperature (Tg), loss factor (tan δ), degree of crosslinking, cure kinetics, protein conformational changes, and molecular bonding compositions. Variations in PGS curing temperature provide differences in physical cues presented to the hMSCs, and work is underway to examine the cellular responses of these hMSCs to microstructured PGS. Ultimately, micro- and nanostructured PGS may be useful tools in the maintenance, differentiation, and control of signaling pathways in hMSCs.