Type I interferons (IFNs) are crucial for activating intracellular antimicrobial programs and influencing innate and adaptive immune responses. They are secreted by infected cells and have three major functions: inducing cell-intrinsic antimicrobial states, modulating innate immune responses, and activating the adaptive immune system. Type I IFNs are protective in acute viral infections but can have protective or harmful roles in bacterial infections and autoimmune diseases. This review summarizes the signaling and epigenetic mechanisms that regulate type I IFN-induced STAT activation and ISG transcription and translation. These mechanisms determine the biological outcomes of type I IFN responses, whether pathogens are cleared or chronic infection or autoimmune disease ensues. Type I IFNs include IFNα and IFNβ, which bind to the IFNα receptor (IFNAR), a heterodimeric transmembrane receptor. The canonical signaling pathway involves the JAK-STAT pathway, leading to the formation of ISGF3, which activates ISGs. ISGs encode proteins that restrain pathogens through various mechanisms. The regulation of type I IFN signaling is influenced by host, pathogen, and environmental factors, which can either augment or suppress the response. Basal IFN signaling is maintained by autocrine loops and is influenced by commensal microbial flora. Augmentation of signaling can occur through increased STAT expression, enhanced phosphorylation, and serine phosphorylation. Suppression involves downregulation of IFNAR, induction of negative regulators, and miRNA-mediated suppression. The qualitative nature of IFNAR signaling is regulated by the activation of different STATs, leading to distinct biological outcomes. The balance between STAT activation is influenced by relative expression levels and other factors. Epigenetic mechanisms, such as chromatin remodeling, histone modifications, and transcriptional regulation, also play a role in modulating ISG expression. Translational regulation of type I IFN responses involves the suppression of translation by ISGs and the activation of specific translation pathways. Chronic type I IFN responses are associated with autoimmune diseases and chronic infections, where they can have immunosuppressive roles. The cross-regulation between TNF and IFN signaling pathways is also discussed, highlighting the complex interactions that influence disease pathogenesis. Overall, the regulation of type I IFN responses is a complex process involving multiple signaling pathways, epigenetic mechanisms, and interactions with other immune factors. Understanding these mechanisms is crucial for developing therapies that can modulate type I IFN responses to promote pathogen clearance and alleviate autoimmune diseases.Type I interferons (IFNs) are crucial for activating intracellular antimicrobial programs and influencing innate and adaptive immune responses. They are secreted by infected cells and have three major functions: inducing cell-intrinsic antimicrobial states, modulating innate immune responses, and activating the adaptive immune system. Type I IFNs are protective in acute viral infections but can have protective or harmful roles in bacterial infections and autoimmune diseases. This review summarizes the signaling and epigenetic mechanisms that regulate type I IFN-induced STAT activation and ISG transcription and translation. These mechanisms determine the biological outcomes of type I IFN responses, whether pathogens are cleared or chronic infection or autoimmune disease ensues. Type I IFNs include IFNα and IFNβ, which bind to the IFNα receptor (IFNAR), a heterodimeric transmembrane receptor. The canonical signaling pathway involves the JAK-STAT pathway, leading to the formation of ISGF3, which activates ISGs. ISGs encode proteins that restrain pathogens through various mechanisms. The regulation of type I IFN signaling is influenced by host, pathogen, and environmental factors, which can either augment or suppress the response. Basal IFN signaling is maintained by autocrine loops and is influenced by commensal microbial flora. Augmentation of signaling can occur through increased STAT expression, enhanced phosphorylation, and serine phosphorylation. Suppression involves downregulation of IFNAR, induction of negative regulators, and miRNA-mediated suppression. The qualitative nature of IFNAR signaling is regulated by the activation of different STATs, leading to distinct biological outcomes. The balance between STAT activation is influenced by relative expression levels and other factors. Epigenetic mechanisms, such as chromatin remodeling, histone modifications, and transcriptional regulation, also play a role in modulating ISG expression. Translational regulation of type I IFN responses involves the suppression of translation by ISGs and the activation of specific translation pathways. Chronic type I IFN responses are associated with autoimmune diseases and chronic infections, where they can have immunosuppressive roles. The cross-regulation between TNF and IFN signaling pathways is also discussed, highlighting the complex interactions that influence disease pathogenesis. Overall, the regulation of type I IFN responses is a complex process involving multiple signaling pathways, epigenetic mechanisms, and interactions with other immune factors. Understanding these mechanisms is crucial for developing therapies that can modulate type I IFN responses to promote pathogen clearance and alleviate autoimmune diseases.