Thermoplastic elastomers (TPEs) exhibit a wide range of properties and are easy to process as they are made of physical, rather than chemical, crosslinks. Many factors contribute to the varied physical properties seen in elastomeric TPEs, defining whether the resultant material is a soft elastomer suitable for adhesives, or a hard elastomer with competitive properties to vulcanized natural rubber. The sustainable polymers studied in this work are able to be synthesized through commercially available reagents and through controlled polymerization methods. Through the design of sustainable block polymers, we have gained insight into properties such as polymer entanglement that govern TPE mechanical behavior. High molar mass systems demonstrate high strength and high extensibility, yielding tough elastomers. Incorporating crystallinity or hydrogen-bonding groups results in improved mechanical properties and reduced stress relaxation. This work presents the synthesis of sustainable polymers and the investigation into the fundamental polymer properties essential to designing high performing TPEs.