Flaveria trinervia (Spreng) C. Mohr is a plant traditionally used in Mexican medicine. In this study, gas chromatography–mass spectrometry (GC–MS) combined with network pharmacology was employed to characterize volatile and semi-volatile metabolites from F. trinervia leaves and to explore their potential system-level mechanisms of action in inflammatory and tumor-related disorders. A dual extraction strategy (hexane/dichloromethane and acetone/chloroform) was applied, followed by GC–MS-based compound identification. Putative molecular targets were predicted using established pharmacological databases, and protein–protein interaction networks were constructed to identify topological features and enriched biological pathways. A total of 11 bioactive compounds were tentatively identified with an identity level of ≥80%, with seven shared between both extracts, including phytol, germacrene D, caryophyllene oxide, pinene isomers, squalene, and 2,2′:5′,2″-terthiophene, metabolites previously reported to exhibit antioxidant, anti-inflammatory, and cytotoxic activities. Network topology analysis identified ESR1, RXRA/B/G, NCOA2, and CYP19A1 as central nodes, reflecting convergence on signaling axes involved in apoptosis, cell proliferation, immune modulation, and transcriptional regulation pathways. Functional enrichment analysis revealed significant associations with KEGG pathways related to immune modulation, neuroendocrine regulation, and cancer-associated pathways. Collectively, these findings suggest a multitarget biological and multipathway pharmacological profile for F. trinervia, consistent with previously reported biological activities. The concordance between in silico predictions and existing experimental evidence strengthens the pharmacological relevance of the identified metabolites and supports their prioritization for further experimental validation, including mechanistic and pharmacokinetic studies, in metabolic, immune, neurological, and cancer-related contexts.