Bacterially mediated struvite usually crystallizes as unusual morphologies. To better understand the relationship between growth habit of struvite and bacterial activity in struvite biomineralization process, Shewanella oneidensis MR-1 was selected as a model microbe to induce struvite mineralization in the synthetic sludge liquor. A combination of bacterial and biomimetic mineralization strategies was adopted. Different bacterial components were isolated from the cultures by a set of separation techniques, and used to influence struvite crystallization and growth. The identification and characterization of the mineralized products were done using XRD, FTIR, FESEM, TG-DTA, XPS, and elemental analysis. Bacterial mineralization experiments demonstrated that S. oneidensis MR-1 cannot only trigger mineralization and growth of struvite, but also mediate the specific morphogenesis of struvite. Biomimetic mineralization experiments revealed that different bacterial components had different effects on struvite morphology, and low molecular-weight peptides secreted by the bacteria played a dominant role. Current results can provide a deeper insight into bacterially mediated struvite morphogenesis, and be potentially applied to phosphorus and nitrogen recovery from various eutrophic wastewaters.