Canine Interferon-Alpha (IFN-α) is a type I interferon produced primarily by plasmacytoid dendritic cells and virus-infected cells in dogs (Canis lupus familiaris), where it plays a central role in early innate antiviral immunity. Upon binding to the type I interferon receptor complex (IFNAR1/IFNAR2), canine IFN-α activates the JAK/STAT signaling pathway, inducing interferon-stimulated genes (ISGs) that inhibit viral replication, enhance antigen presentation, and promote activation of natural killer (NK) cells and adaptive immune responses. In canine health, IFN-α is critically involved in host defense against viral infections such as canine parvovirus, canine distemper virus, canine influenza virus, and canine adenovirus, and altered interferon responses can influence disease severity and viral persistence. Recombinant interferons have also been explored for therapeutic use in viral and immune-mediated conditions. Importantly, dogs serve as valuable spontaneous animal models for human infectious diseases, autoimmune disorders (such as immune-mediated hemolytic anemia), and certain cancers, where type I interferon signaling contributes to antiviral defense, tumor immune surveillance, and immunomodulation. Characterization of canine IFN-α therefore supports vaccine development, antiviral strategy research, oncology studies, and comparative investigations of interferon biology relevant to both veterinary medicine and translational human health research.