Kale (Brassica oleracea var. acephala), a member of the cruciferous (Brassicaceae) family, has gained significant popularity as a nutritionally dense leafy vegetable in recent years, attributed to its rich nutraceutical properties, including phytochemicals, antioxidants, and antiproliferative compounds. These properties play a critical role in addressing global nutritional deficiencies through cost-effective dietary sources, leading to kale’s designation as a superfood by the research community. Its popularity has steadily increased, particularly in the United States. To meet the growing demand for kale, optimizing production systems is essential. In this study, we evaluated leaf physiology, yield parameters, and nutrient content across kale cultivars grown under both organic and conventional farming systems. We observed substantial variation in leaf photosynthesis and other physiological traits, reflecting the different responses of cultivars to cultivation methods. Additionally, significant differences in mineral content and total soluble proteins were noted, with organic farming practices notably enhancing soluble proteins, leaf nitrogen content, nitrate nitrogen (NO3-N), and several key minerals compared to conventional practices. These findings suggest that organic farming practices may enhance the nutraceutical quality of kale, potentially offering superior nutritional benefits compared to conventional methods systems.