Perovskite oxides, particularly double perovskite oxides, have drawn significant research interest within the fields of solid‐state chemistry and materials science. As a quintessential double perovskite oxide, Sr2Fe1.5Mo0.5O6‐δ (SFM) has unique electronic, magnetic, and catalytic properties. These attributes make it a promising candidate for energy conversion and storage applications. This review offers a comprehensive overview of advancements using SFM across various applications, including solid oxide cells, protonic ceramic cells, and electrocatalysis. Notably, the review highlights emerging optimization strategies that enhance functionality based on a fundamental understanding of the reaction mechanisms. The review concludes by discussing the persistent challenges facing SFM‐based functional materials, as well as their prospects, considering both fundamental research and industrial applications.