This study aimed at identifying seaweed species with optimal characteristics to develop multifunctional foods for metabolic syndrome (MetS) management. Mass spectrometry chemical characterization and bioactive profile evaluation of methanolic extracts from seven commonly consumed seaweeds were compared. Monomeric sugars namely mannitol, fucitol, xylitol and their sulphated analogs as well as lipids (phosphatidic acid, octadecenoic acid, and prostaglandin 2α) were detected in seaweeds. Himanthalia elongata showed the highest phenolic content (24.04 µmol GAE/g), and antioxidant activity. This species was the only one showing angiotensin converting enzyme-I inhibitory activity (IC50 = 65 µg/mL). U. pinnatifida and H. elongata extracts were notably more effective reducing pro-inflammatory molecules in lipopolysaccharide-induced RAW 264.7 macrophages. Finally, Ulva spp., Palmaria palmata, U. pinnatifida and H. elongata significantly inhibited triglyceride accumulation in mature 3T3-L1 adipocytes (43–52% inhibition). Among seaweeds, H. elongata showed the highest potential to be used as ingredient in the development of new functional foods for MetS management.