Cancer remains a leading cause of mortality worldwide, and new chemical leads are essential for developing potent anticancer therapies. Evidence suggests that Pseudomonas aeruginosa (Pa) may suppress tumorigenesis, although the underlying mechanisms remain largely unclear. This study characterized a novel small molecule quinolone, JH62 (E-2-(tridec-4-en-1-yl)-quinolin-4(1H)-one, C22H31NO), from Pa. JH62 exhibited broad-spectrum anticancer activity, inhibiting the proliferation of A549 lung cancer cells in a time- and dose-dependent manner with an IC50 of 15 μM, while showed low cytotoxicity toward normal cells. In xenograft mice model, treatment with JH62 (10 mg/kg) reduced tumor weight and volume by 73% and 79%, respectively. Mechanistically, treatment with JH62 induced structural and functional disruption of mitochondria in cancer cells, triggered autophagic cell death, and did not cause DNA damage. Genetic analysis confirmed that JH62 biosynthesis depends on the pqsABCDE gene cluster and that JH62 positively regulates its own production. ADMET profiling further indicated promising drug-like properties for future development. These findings establish JH62 as a promising anticancer lead compound derived from microbial metabolism.