Obesity presents a significant challenge in managing patients with craniopharyngioma (CP). Cyst fluid (CF), rich in inflammatory mediators, is implicated in CP‐related obesity, though the precise mechanism remains unclear. This study investigated the impact of CF or C‐X‐C motif chemokine ligand‐1 (CXCL1) injections on body weight, Lee index, plasma lipid profiles, hepatic lipid accumulation, leptin levels, NF‐κB pathway, the suppressor of cytokine signaling 3 (SOCS3) expression, and leptin sensitivity in rats. Bioinformatics was employed to identify differentially expressed genes (DEGs) between CF/CXCL1‐treated and control SY5Y cells, as well as to confirm enriched pathways. Western blotting was used for experimental validation, including the effects of sodium salicylate (SS) on leptin sensitivity in SY5Y cells. Injecting CF or CXCL1 into the brain, without hypothalamic damage, led to increased body weight, Lee index, and hepatic lipid accumulation in rats, alongside elevated fasting blood glucose, triglycerides, and total cholesterol, while high‐density lipoprotein cholesterol levels decreased. Additionally, CF and CXCL1 could induce elevated leptin levels, a higher leptin‐to‐body weight ratio, and resistance to exogenous leptin by activating the NF‐κB pathway and upregulating the expression of SOCS3 in rats. Further validation confirmed that CF and CXCL1 suppress leptin signaling by activating the NF‐κB pathway and upregulating SOCS3. Moreover, SS mitigated the inhibitory effects of CF or CXCL1 on leptin signaling, preserving leptin sensitivity in SY5Y cells. These results highlight the obesogenic role of CF and CXCL1, offering insights into the development of morbid obesity through inflammatory factor‐mediated leptin resistance, independent of hypothalamic damage. SS may serve as a promising therapeutic approach for CP‐associated obesity, though additional clinical studies are necessary to confirm its efficacy.