This chapter addresses the insight knowledge and future prospects of the plant growth-promoting rhizobacteria (PGPR) their mode of actions, developments effects on plant physiology, and morphology induced by PGPR. PGPR strains have diverse and worthwhile applications as bioinoculants, biofertilizers, and biocontrol agents (BCA), with practical potential proved as a boon in environment-friendly sustainable agriculture. Sustainable agriculture is a comprehensive concept which embraces advances in agricultural management practices and technology with the ever-increasing food and feed demands for increased population. Efficient and potential soil microbiota with implication of PGPR is an alternative for sustainable agricultural practices. Advantage of PGPRs is increasing rapidly in order to utilize them as commercial eco-friendly biofertilizers. PGPRs change the complete microbial community structures present in the rhizosphere and thus efficiently enhanced the plant growth. Nitrogen is the most essential element for all the form of life and it is a vital nutrient for the plant growth and productivity.