Glaucosciadium cordifolium (Apiaceae) is traditionally used against stomach ailments, as aphrodisiac and appetizer. This study endeavored to characterize several extracts of G. cordifolium aerial parts (prepared by various isolation procedures (ASE: Accelerated solvent extraction; HAE: homogenizer-assisted extract; MAE: Microwave-assisted extraction; MAC: Maceration; SFE: supercritical CO2 extraction; SOX: Soxhlet; UAE: Ultrasound-assisted extraction) and evaluate the antioxidant activity and inhibitory activity against clinical enzymes. In order to describe the composition of the extracts liquid chromatography-mass spectrometry (LC-MS) analysis was employed. Of the total number of confirmed polyphenol components (15 in total), four were dominant in their content: 5-O-caffeoylquinic acid, p-coumaric acid, quercetin-3-O-glucoside and quercetin-3-O-rhamnoside. Spectrophotometric analysis showed that the total phenolic and flavonoid contents differed among the extracts, which was influenced by extraction technique used for their preparation. The phenolic content of the different extracts varied in the order HAE > UAE > MAC > SOX > MAE > ASE > SFE. HAE extract yielded the highest phenolic content (49.97 mg gallic acid equivalent (GAE)/g) while SFE demonstrated the lowest phenolic content (21.65 mg GAE/g). MAC extracts contained the highest flavonoids (50.35 mg rutin equivalent (RE)/g) while SFE extract showed the lowest flavonoid content (10.87 mg RE/g). UAE, MAC, MAE, HAE, SOX and ASE showed significant DPPH antioxidant activities and the values of radical inhibitory capacity varied in the range of 55.79–54.99 mg TE/g. SFE demonstrated weak DPPH (1,1-diphenyl-2-picrylhydrazyl) radical inhibitory activity with a value 7.0 mg TE/g. UAE showed the highest ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) cation radical inhibitory potential (122.41 mg trolox equivalent (TE)/g). The CUPRAC (cupric reducing antioxidant capacity) activity of UAE was remarkable with a value of 193.58 mg TE/g. A gradual decrease in activity was observed with extracts obtained from other extraction techniques with the lowest antioxidant activity (77.0 mg TE/g) obtained from SFE extract. The highest antioxidant recorded by Phosphomolybdenum was found in HAE extract (1.62 mmol TE/g). SFE showed the highest metal chelating activity (27.30 mg ethylenediamine tetraacetic acid (EDTAE)/g). Regarding the acetylcholinesterase (AChE) inhibitory activity, MAE and ASE extracts showed the highest potential with a value of 4.06 and 4.05 mg galanthamine equivalent (GALAE)/g respectively. All tested extracts showed considerable whitening activity and SFE revealed the highest activity against tyrosinase (93.82 mg kojic acid equivalent (KAE)/g). In addition, SFE showed the best inhibitory ability against amylase (0.71 mmol acarbose equivalent (ACAE)/g). However, the extracts had similar glucosidase inhibitory effects (1.64–1.71 mmol ACAE/g). The rich chemical composition of the extracts and joint action of different classes of polyphenolic compounds in them may be responsible for their high biological activity. Extracts with the highest activity could serve in the future as an important tool for controlling the activity of clinically important enzymes and take their place in the official formulation after additional pharmacological tests.