Lamium orientale E.H.L. Krause is a herbaceous annual plant species in the Lamiaceae family. In the present study, anticancer, antioxidant, antibacterial, enzyme inhibitory, and quorum sensing inhibitory (on the inhibition of biofilm formation and violacein pigment production) activities of infusion and methanol (MeOH) extracts of roots, stems, leaves, and flowers of L. orientale were evaluated. The total phenolic-flavonoid contents and the phytochemical profiles of the extracts were determined using colorimetric assays and high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS), respectively. The leaf extracts had the maximal levels of flavonoids and phenolics. Chlorogenic acid was most concentrated in the extracts. Based on several antioxidant activity assays, the MeOH extract of the flowers and infusion extract of the leaves had potent antioxidant activities. The MeOH extract of the stems exhibited the highest activities against acetylcholinesterase and butyrylcholinesterase, while the MeOH extract of the roots demonstrated the highest activities against tyrosinase, amylase, and glycosidase. The highest anticancer activity was determined for the MeOH extract of the roots against the MCF-7 cells (IC50=425.7 µg/mL). The MeOH extract of leaves and all infusion extracts significantly inhibited biofilm formation in Pseudomonas aeruginosa. The results suggested that L. orientale extracts may have significant potential for developing new therapeutic approaches owing to their high content of bioactive molecules.