Abstract: 3-Hydroxydecanoic acid (3-HDA) is a bacterial metabolite with antibacterial and immune-inducing activities. In this study, germination assays and pot experiments were performed to investigate the effects of exogenous 3-HDA on seed germination, plant growth, yield, and quality of ‘cherry radish’. The results showed that seed soaking with 30 mg/L 3-HDA significantly promoted seed germination. The germination rate at 12 h increased by 58.2%, and the radicle length increased by 36.6% compared with the control (CK). In pot experiments, root drenching with 150 mg/L 3-HDA significantly increased the yield of ‘cherry radish’. The average single root weight increased by 38.5% compared with CK. The treatment markedly improved the fruit quality, with vitamin C, soluble sugar, and soluble protein contents increased by 12.6%, 44.1%, and 15.6%, respectively. Furthermore, 3-HDA treatment significantly enhanced the activities of ascorbate peroxidase (APX) and peroxidase (POD) and reduced the content of malondialdehyde (MDA) in ‘cherry radish’. These findings indicate that treatment with an appropriate concentration of 3-HDA effectively promotes the growth, improves the quality, and enhances the antioxidant capacity of ‘cherry radish’. This provides a scientific basis for the application of 3-HDA in efficient, high-quality vegetable production.