Cupressus sempervirens L. which is largely used in traditional medicine was collected from the Florya Atatürk Forest (İstanbul, Türkiye) to investigate the phytochemical profiling and antioxidant capacity of the seeds and cones. The antioxidant activities of hexane and methanol extracts of C. sempervirens L. were assessed in vitro using five complementary methods, including the β-carotene-linoleic acid assay for lipid peroxidation activity, the DPPH•, ABTS• assays for radical-scavenging activity, the CUPRAC method, and metal chelating methods. In addition, the phenolic profiling of the methanol extracts of the seeds and cones was analyzed using LC-HR/MS, for the first time. According to the findings, the antioxidant activity of the methanol extract obtained from seeds appears to be higher than that of cones in all assays. The methanol extracts of the seeds showed higher activity with an IC50: 24.081.06, IC50: 6.080.19, and A0.5: 18.600.63 µg/mL in the DPPH•, ABTS•, and CUPRAC assays, respectively than the BHA, and α-TOC. Also, the methanol extract of the cones showed strong activity with an IC50: 38.870.03 and A0.5:103.534.33 in ABTS• scavenging and CUPRAC assays. Moreover, twenty-eight phenolics were determined in the seeds while twenty-one phenolics were determined in the cones of the C. sempervirens using LC-HR/MS. The amounts of fumaric acid, vanilic acid, (-)-epicatechin, quercetin, hispidulin 7-glucoside, hyperoside, and quercitrin in the seeds are higher than those in the cones. Therefore, the results suggested that there was a strong relationship between the antioxidant activities of the extracts and their phenolic ingredients.