To investigate the efficacy of enzymatic extract of Ecklonia cava and its polyphenol extract (AG-DK) as cosmetic ingredients, the anti-oxidative effect, anti-glycation effect, anti-melanogenic effect, and anti-inflammatory effect of the extracts were evaluated in vitro. The enzymatic extract of E. cava (SC50 42.9 ppm) and AG-DK (SC50 6.4 ppm) showed a strong DPPH free radical scavenging activity. The anti-glycation ability of the enzymatic extract of E. cava and AG-DK was tested using bovine serum albumin (BSA), which inhibited the formation of advanced glycation end-products (AGEs) in the BSA/glucose system. The enzymatic extract of E. cava (IC50 97.2 ppm) and AG-DK (IC50 7 ppm) had inhibitory effects on tyrosinase activity. Moreover, the enzymatic extract of E. cava and AG-DK had an anti-inflammatory effect through the inhibition of nitricoxide (NO) and prostaglandin E2 (PGE2). These findings suggest that the enzymatic extract of E. cava and AG-DK can be applied to skin-care products as cosmetic ingredients.