Foam injection molding (FIM) is an advanced technology for preparing lightweight plastic foams, but its inferior mechanical performance remains a challenge. In this study, microcellular injection‐molded β‐polypropylene (β‐PP) foams with high ductility were successfully prepared by combing the β‐nucleating agent with controllable temperature field. Foaming results showed that the microcellular β‐PP foams exhibiting a cell size of about 8 μm and cell density over 108 cells/cm3 were prepared with a crystalline diameter approximately 5 μm, while PP foams had a rather large cell size approximately 150 μm and low cell density of 105 cells/cm3 with 30 μm crystalline size. As a result, this significant improvement in cell structure as well as the crystalline size lead to a significant increment of 86% for the ductility of β‐PP foams. This work offers a facile strategy to prepare injection‐molded foams with desirable mechanical properties for their wide range of applications, such as automotive construction and consumer electronics.