Circular RNAs (circRNAs) are single-stranded, closed-circular RNAs, which bind to other RNAs or proteins to regulate their functions. The importance of circRNAs during virus infection has been largely elusive. Here, we identified that a circRNA, hsa_circ_0001400, is induced upon infection with various pathogenic viruses including Kaposi sarcoma herpesvirus (KSHV) and controls viral and human gene expression so that infected human cells have less virus production but better cell growth. KSHV has two phases: latent and lytic cycle. circ_0001400 biases cells to the latent cycle during which viruses express only a limited number of genes to survive for the life of the host. Our results revealed a novel virus-host interaction via circRNAs to maintain latency after infection with an oncogenic virus.