The green kiwi (Actinidia deliciosa) is originally from China and is widely known and consumed worldwide for its outstanding nutritional and functional properties that give it a high presence of antioxidant compounds. The high consumption level of this fruit, both in its native form and in products derived from its industrialization, including juices, wines, jams, and dehydrated fruits, among others, produces by-products such as skin (GKS) and bagasse (GKB). These were traditionally used for the generation of compost, discarded, or burned. However, current research indicates that they constitute a natural source of antioxidant compounds with broad beneficial potential for health. In this sense, GKS and GKB are characterized from nutritional and chemical points of view. Nutritional characterization (proteins, lipids, and minerals) was carried out following the international standards of the AOAC International. For chemical characterization, heat-assisted extraction (HAE) was applied followed by a metabolomic study by HPLC-ESI-QqQ-MS/MS that allowed us to identify and quantify the metabolites. This study reports that GKS and GKB constitute a source of nutrients, with GKB highlighting 8.62 g/100 dw of protein and 8.60 g/100 dw of lipids, of which 42% corresponds to polyunsaturated fatty acids. In contrast, GKS stands out for its high content of K+, Ca+, P+, and Mg+ minerals. This metabolomic study reports GKS 48.5% of phenolic acids, 29.8% of flavonoids, and 21.7% of other polyphenols, while GKB contains 60.5% of phenolic acids, 15.4% of flavonoids, and 24.1% of other polyphenols. These findings reinforce the theory that GKS and GKB constitute a natural source of compounds with antioxidant properties, which may have food, pharmaceutical, and cosmetic applications, providing benefits for human health.