The use of gamma irradiation to promote phytochemical components in various plants, including microalgae, has gained increasing attention in recent years. The objective of this investigation was to evaluate the metabolic profiling of bioactive phytochemical constituents and to assess antioxidant activities in Arthrospira platensis after treatment with γ-irradiation at a dose of 700 Gy following 20 days of growth. The data from this study revealed a significant increase in antioxidant capacities, including DPPH˙, FRAP, ABTS˙⁺, total antioxidant capacity, proanthocyanidins, saponins, β-carotene, protein, amino acids, and polyphenol fractions (flavonoids and phenolics) in γ-irradiated A. platensis compared to the control samples. Protein constituents typically include 24 standard amino acids, but some amino acids (such as cysteine and lysine) were not detected in A. platensis. However, the alga contains eighteen essential amino acids in sufficient concentrations. In this investigation, metabolomic profiling revealed the identification and quantification of fifteen polyphenol fractions (ten phenolics and five flavonoids) in A. platensis. This study supports the potential health benefits of incorporating metabolites from γ-irradiated A. platensis into functional foods, medicinal foods, and nutritional supplements, offering numerous advantages for the food industry. Therefore, the use of γ-irradiated A. platensis metabolites may contribute, directly or indirectly, to promoting health, as these metabolites are natural, safe, affordable, accessible, and easy to obtain.