Some species of the genus Cousinia (family Asteraceae) are traditionally used to treat various diseases, and scientific research has demonstrated that they possess interesting biological activities. This study offers the first comprehensive evaluation of the aerial parts of Cousinia iconica Hub.-Mor, incorporating phytochemical profiling, bioactivity assays, and network pharmacology. High-resolution LC–ESI-QTOF–MS analysis revealed that the plant is rich in phenolic acids, hydroxy- and methoxy-flavonoid glycosides, and lignans. The aqueous extract contained the highest levels of total phenolics (78 mg gallic acid equivalents/g) and flavonoids (15.5 mg rutin equivalents/g). It also exhibited the strongest radical scavenging, reducing power, and metal chelating activities. Biological tests showed that, while all three organic extracts had similar cytotoxic effects against the RKO colorectal cancer cell line, none demonstrated measurable antiviral activity against HHV-1 or human coxsackievirus B3. In silico analyses supported these results by identifying 22 disease-relevant targets of C. iconica compounds linked to head and neck squamous cell carcinoma (HNSCC). Molecular docking showed strong binding affinities of key phytochemicals to cancer-related targets (CDK2, CHEK1, PDGFRA) and metabolic enzymes (acetylcholinesterase, butyrylcholinesterase, tyrosinase, amylase, glucosidase). Overall, the results highlight C. iconica as a promising source of bioactive phenolic compounds with significant cytotoxic potential, though its antiviral effects appear limited. Further research, especially on isolated constituents and mechanism-based assays, is necessary to better understand its therapeutic potential.