A thorough understanding of how grain sorghum develops is essential in determining how best to manage this crop. Grain sorghum has three predictable phases of growth: vegetative (planting to panicle initiation); reproductive (panicle initiation to flowering) and grain filling (after flowering to maturity). This chapter describes each of the phases in detail, observing how each stage is affected by factors such as genotype, temperature and photoperiod. Climatic conditions for optimal growth, as well as the effects and physiological basis of drought, high temperature and elevated carbon dioxide tolerance, are discussed. Due to climate change, sorghum-producing areas are facing increased exposure to water deficits and extreme temperatures, making comprehension of plant response to environmental stresses even more necessary. It is concluded that the use of high-yielding varieties and proper management practices will be essential to the future of this crop.