(1) Background: This study aimed to investigate the feasibility of using Maackia amurensis branch extract as a cosmetic ingredient with skin-whitening and antiwrinkle effects. (2) Methods: The skin-whitening effect of M. amurensis branch extract was confirmed by investigating α-melanocyte-stimulating hormone (α-MSH)-induced melanin synthesis and melanogenic protein expression in B16F1 cells. The antiwrinkle effect of M. amurensis branch extract was verified by assessing matrix metalloproteinase (MMP)-1 expression and soluble collagen content in CCD-986sk cells. The major compounds in M. amurensis branch extract were identified through isolation and characterization and confirmed by high-performance liquid chromatography analysis. (3) Results: M. amurensis branch extract significantly inhibited α-MSH-induced melanin synthesis by 49%, 42%, and 18% at 50, 37.5, and 25 μg/mL concentrations, respectively, compared with the negative control (NC). M. amurensis branch extract also significantly reduced the expression of the microphthalmia-associated transcription factor, tyrosinase-related protein (TRP)-1, TRP-2, and tyrosinase in B16F1 cells. Furthermore, M. amurensis branch extracts decreased ultraviolet A-induced MMP-1 expression and increased soluble collagen synthesis in CCD-986sk cells. In addition, the major compounds present in M. amurensis branch extract were found to be formononetin, genistein, trans-resveratrol, piceatannol, and tectoridin. (4) Conclusions: M. amurensis branch extract has skin-whitening and antiwrinkle properties. Therefore, it can be used as an ingredient in functional cosmetics with skin-whitening and antiwrinkle effects.