Amaranthus Caudatus is an underutilized, climate-resilient pseudo-cereal crop that contains excellent nutritional, physiological, and biological characteristics for sustainable agriculture and soil management. It contains good proteins (14–17%), high lysine levels, and major nutrients such as minerals, hence a good food source to individuals with protein-energy malnutrition. The crop is a good to be planted under water stress conditions, high temperature, and low nutrient content in the soil due to its high C4 photosynthetic and robust antioxidant system. This makes the crop to show high-water use efficiency of up to 35%. The plant has a deep taproot system, which is approximately up to 1.5 m long, with lateral roots. This enhances the nutrient and water uptake as well as physical properties of soil by enhancing aggregation. The crop also possesses high diversity of microbes due to rhizodeposition, and therefore supports large quantities of the Plant growth-promoting rhizobacteria (PGPR) and Arbuscular mycorrhizal fungi (AMF). However, crop productivity can be made stable by 20 to 40% by the implementation of sustainable methods such as organic farming, integrated nutrient management, conservation agriculture and intercrops, which will reduce overreliance on agrochemicals. Potential grain crop productivity of 1.5–2 t ha−1 under low input agriculture conditions has been estimated by the use of crop modeling software such as HYDRUS-1D, DSSAT, and APSIM. Crop phenology, productivity, and resource use efficiency was simulated under various agroclimatic conditions (altitudes ranging between 0 to 3000 m). Amaranthus caudatus could enhance the livelihood of small farmers, guarantees the sovereignty of their seeds, and augments the security of people to consume it.