Hepatocellular carcinoma (HCC) is one of the most aggressive types of liver cancer, and it is frequently associated with upregulated c-Myc expression. Sorafenib (Sor) is commonly used to treat HCC, but many patients experienced mild to severe side effects due to prolonged Sor treatment during therapy. It has been known that Pentagamavunone-1 (PGV-1) exhibits a remarkable antiproliferative effect on several cancer cells, yet limited studies have reported its cellular activities in HCC. The current study aims to evaluate the anticancer effects of Sor in combination with PGV-1 on the progression of HCC proliferation. c-Myc expressing cells, JHH-7 and Huh-7, were used for this study, then Sor and PGV-1 were tested for their effect on the cellular physiology phenomena including cytotoxicity combination assay and colony formation assay, cell cycle profile and reactive oxygen species (ROS) level by flow cytometry, senescence induction by beta-galactosidase (SA-β-gal) assay, and migration inhibition by wound healing assay. The c-Myc expression was evaluated through Western blot. PGV-1 was more effective than Sor at inhibiting cell growth, and it showed greater selectivity for HCC over fibroblast cells. The combination of Sor with PGV-1 exhibited synergistic-additive cytotoxicity with an irreversible effect in HCC cell lines. The combination induced senescence similarly with Sor alone in JHH-7 cells, while PGV-1 enhanced the cellular senescence when combined with Sor in Huh-7 cells. Furthermore, the combination increased ROS level in the same way as PGV-1 did in HCC. The combination with PGV-1 acted better than Sor alone to inhibit JHH-7 cell migration. In addition, the combination treatment led to the suppression of c-Myc, particularly in JHH-7 cells. Taken together, combining Sor with PGV-1 promotes better efficacy than Sor alone to inhibit HCC cell proliferation, and further evaluation of the efficacy and safety of adding PGV-1 to Sor in HCC therapy is worthwhile as a potential combination treatment option.