Hepatic stellate cells (HSCs), located in the subendothelial space of Disse, are the principal non-parenchymal cells responsible for extracellular matrix (ECM) production during liver fibrosis. Platycodin D (PD), a triterpenoid saponin isolated from the root of Platycodon grandiflorum, is known to exhibit pharmacological properties such as anti-inflammatory, antitumor, and anti-allergic effects. However, the effects of PD on TGF-β1-induced HSC activation and the underlying molecular mechanisms remain largely unclear. Therefore, this study aimed to investigate the anti-fibrotic effects of PD on TGF-β1-induced HSC activation. PD showed no cytotoxic effects at concentrations up to 10 μM and dose-dependently suppressed TGF-β1-induced cell proliferation and expression of alpha-smooth muscle actin (α-SMA) and collagen type I alpha 1 (Col1α1). PD induced the phosphorylation of CaMKII, AMPK, and CREB, thereby reducing TGF-β1-induced Smad2/3 phosphorylation. In conclusion, these findings suggest that PD suppresses TGF-β1-induced HSC activation by inhibiting α-SMA and Col1α1 expression through activation of the CaMKII/AMPK/CREB signaling pathways and inhibition of Smad2/3 signaling. These results indicate that PD may serve as a potential therapeutic candidate for the treatment of liver fibrosis.