Parthenium hysterophorus L., an invasive alien species and notorious weed, offers various benefits to the medical and agrochemical industries. This study aimed to evaluate the antioxidant and insecticidal activities of P. hysterophorus flower extract and conduct chemical profiling to identify the phytoconstituents responsible for these biological effects. The antioxidant activity was assessed using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, while gas chromatography mass spectrometry (GCMS) analysis was employed for chemical configuration evaluation. Our findings demonstrate that the dichloromethane (DCM) extract of P. hysterophorus exhibits potent radical scavenging activity (95.03%). Additionally, phytochemical analysis revealed significant amounts of phenols and flavonoids in the distilled water and ethyl acetate extracts (103.30 GAEg-1 and 138.67 QEg-1, respectively). In terms of insecticidal activity, the flower extract displayed maximum mortality rates of 63.33% and 46.67% after 96 hours of exposure at concentrations of 1000 μgmL-1 and 800 μgmL-1, respectively, with similar trends observed at 72 hours. Furthermore, the P. hysterophorus extracts exhibited LC50 values of 1446 μgmL-1 at 72 hours and 750 μgmL-1 at 96 hours. Imidacloprid, the positive control, demonstrated higher mortality rates at 96 hours (97.67%) and 72 hours (91.82%). Moreover, the antioxidant activity of P. hysterophorus extracts exhibited a strong correlation with phenols, flavonoids, and extract yield. GCMS analysis identified 13 chemical compounds, accounting for 99.99% of the whole extract. Ethanol extraction yielded the highest percentage of extract (4.34%), followed by distilled water (3.22%), ethyl acetate (3.17%), and dichloromethane (2.39%). The flower extract of P. hysterophorus demonstrated significant antioxidant and insecticidal activities, accompanied by the presence of valuable chemical compounds responsible for these biological effects, making it a promising alternative to synthetic agents. These findings provide a novel and fundamental basis for further exploration in purifying the chemical compounds for their biological activities.