Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths worldwide. Currently, only chemoembolization and sorafenib have shown survival benefits for advanced HCC. There are major unmet needs in HCC management and the discovery of new therapeutic targets. Here we identified NCAPG (non-SMC condensin I complex, subunit G) as a novel mitotic gene required for HCC cell proliferation and migration through siRNA knockdown of a panel of novel overexpressed genes in HCC based on The Cancer Genome Atlas (TCGA) dataset. We found that knockdown of NCAPG induces HCC cell mitosis and inhibits cell growth, proliferation, and migration in vitro. Tetracycline-inducible shRNA knockdown of NCAPG inhibits tumor growth of HCC cells in vivo. Moreover, overexpression of NCAPG in clinical HCC samples was associated with recurrence and survival of patients. The overexpression of NCAPG was significantly correlated with the overexpression of CCNB1 (G2/mitotic-specific cyclin B1), a regulatory protein involved in mitosis. Therefore, NCAPG may provide a promising novel therapeutic target for the treatment of advanced HCC in the future.