This study investigates the effect of glycerol monosterate (GMS) on the crystallization behavior of hard segment (HS) domains in the TPU microstructure. Further, the batch foaming technique was used to investigate the foaming behavior of TPU samples compounded with GMS (TPU-GMS) and neat TPU. The differential scanning calorimetry (DSC) analysis revealed that the overall crystallinity of TPU-GMS increased significantly compared to neat TPU as observed by the increase in the total heat of fusion. It was also observed that the melting endotherm of TPU-GMS sample showed formation of a broad high melting peak above 170°C, which suggests formation of crystalline HS domains. Atomic Force Microscopy (AFM) results revealed presence of highly ordered micro-crystalline HS domains in TPU-GMS sample supporting the results discussed earlier. Comparing the foam characteristics of neat TPU and TPU-GMS, it was observed that both samples exhibited microcellular morphologies with high cell density over wide temperature ranges of 150 °C and 170°C. However at high foaming temperature (170°C), neat TPU foams showed high cell coalescence compared to TPU-GMS. Furthermore, TPU-GMS samples showed much higher expansion ratio compared to neat TPU over wide range of processing temperatures. The lubricating effect of GMS assists the HS to stack together and form crystalline domains. These HS crystalline domains are present at high temperature acting both as heterogeneous nucleating sites as well as reinforcement leading to the observed microcellular morphology with high expansion ratio in TPU-GMS samples.