Interferons are a group of signaling proteins made and released by host cells in response to the presence of several viruses. This study focused on interferon-related developmental regulator 1 (IFRD1) from Epinephelus akaara, an immediate early gene that encodes interferon-gamma protein. According to previous reports, IFRD1 could play a role in regulating gene activity in the cell proliferative and differentiative pathways. It also helps maintain the immune system stability against virus invasion. EaIFRD1 contains an open reading frame of 1,287 bp, encoding a predicted protein of 428 amino acids with a calculated molecular mass of 48.22 kDa. The EaIFRD1 protein contains a long interferon-related developmental regulator superfamily domain between 21 and 325 amino acids. To check the spatial expression analysis, twelve different tissues were used, and the brain has the highest level of EaIFRD1 expression among those tissues, whereas skin tissue has the lowest level. Further, blood, spleen, and kidney tissues of E. akaara were used to identify the immune-related response of EaIFRD1 against different immune stimulants. Relative mRNA expression of EaIFRD1 in blood, liver, and spleen was significantly modulated in response to polyinosinic:polycytidylic acid (poly I:C), bacterial endotoxin lipopolysaccharides (LPS) and nervous necrosis virus (NNV). Results revealed that EaIFRD1 expression was significantly upregulated at 6 h in the liver and spleen against the poly (I:C). All three tissues showed the highest mRNA expression 6 h after the post-infection of LPS. Furthermore, to evaluate the antiviral effect of EaIFRD1, we observed the expression of type ? interferon pathway-related gene expression such as; interferon-stimulated gene 15 (ISG15), Myxovirus-resistance (Mx), and Viperin (Vip) by infecting the fathead minnow (FHM) cells with viral hemorrhagic septicemia virus (VHSV). After 12 h of infection, those three genes showed a rapid increment of expression in EaIFRD1 transfected samples compared to the control. Functional assays revealed the antiviral, antiapoptotic, and immune regulation responses of overexpressed EaIFRD1. Collectively, these findings indicate that EaIFRD1 is vital for the immune system of red spotted grouper by activating the interferon pathways as it stimulates and regulates the defense responses during viral infection.