Chronic hepatitis C virus (HCV) infection is a leading cause of liver cancer. HCV propagation and oncogenicity depend in part on the phosphorylation states of its non-structural protein 5A (NS5A); however, little is known about how hypo- or hyper-phosphorylated NS5A functions. Here, we segregated hypo- from hyper-phosphorylated NS5A in HCV-infected Huh7.5.1 cells with two custom-made specific antibodies and differentiated their interacting proteins with dimethyl labeling-based quantitative proteomics. Bioinformatics analysis revealed that hyper-phosphorylated NS5A preferentially binds the polymerase II-associated factor 1 complex known to alter host gene expression involved in cancer progression. In contrast, hypo-phosphorylated NS5A binds proteins involved in host antiviral response. Moreover, we found that the hypo-phosphorylated NS5A binds DNA-dependent protein kinase catalytic subunit (DNA-PKcs) predicted to phosphorylate NS5A at serine 232, a key amino acid that governs NS5A transition from hypo- to hyper-phosphorylation state. Inhibition of DNA-PKcs with an inhibitor or via gene-specific knockdown significantly reduced serine 232 phosphorylation and NS5A hyper-phosphorylation. Collectively, we have identified a protein kinase that regulates a delicate balance of NS5A between hypo- and hyper-phosphorylation states respectively involved in host antiviral responses and liver cancer progression.