A growing focus in nutritional psychiatry is examining dietary interventions as a therapeutic strategy for depression. Chlorogenic acid (CGA), a naturally occurring polyphenol, has demonstrated promising anti-inflammatory and neuroprotective effects. This study aimed to elucidate the underlying molecular targets and mechanisms responsible for CGA's antidepressant-like actions. The potential targets and pathways of CGA related to FoxO3a were initially predicted using network pharmacology and molecular docking. In vitro, the protective effects of CGA were investigated in H2O2-stimulated HT-22 cells by assessing cell viability, reactive oxygen species (ROS) levels, mitochondrial membrane potential, and the expression of mitophagy-related proteins. In vivo, a depression model was established in male mice via intraperitoneal injection of lipopolysaccharide (LPS). The antidepressant efficacy of CGA was evaluated through a behavioral test battery. Microglial activation was detected via immunofluorescence. Furthermore, mitochondrial ultrastructure was examined by transmission electron microscopy (TEM), and the expression of mitophagy-related proteins was additionally validated by Western blotting. Finally, the direct interaction between SIRT1 and FoxO3a was examined by co-immunoprecipitation. In vitro, CGA pretreatment improved HT-22 cells viability under H2O2-induced oxidative stress, reduced ROS levels, and restored mitochondrial membrane potential. In vivo, CGA reduced neuroinflammation by lowering the levels of proinflammatory cytokines interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), inhibited microglial activation, and alleviated depressive-like behaviors in LPS-treated mice. Additionally, CGA activated the sirtuin 1 (SIRT1) / forkhead box O3a (FoxO3a) / PTEN-induced kinase 1 (PINK1) / Parkin signaling pathway, promoting hippocampal mitophagy. The antidepressant-like effects of CGA were suppressed upon SIRT1 antagonism with EX527. This study suggests that CGA may serve as a potential therapeutic agent for depression.