Sustainable agriculture is an ongoing research strives for meeting society’s current food demand without compromising the future need and development. Maintaining soil fertility for quality farming is one of the essential parts. However, the wide application of synthetic agrochemicals (e.g., chemical fertiliser) has been a significant contributor to environmental pollution. This review aims to assess the potential of Rhodopseudomonas palustris (R. palustris), a purple non-sulphur bacterium, as a commercialised bio-fertiliser to sustainably promote plant growth. R. palustris is evaluated based on two defined pillars of sustainability, including the effects on plant growth, environmental impact, and feasible production. The effectiveness is based on the improvement of plant growth through the secretion of extracellular metabolites, resistance to abiotic stresses, bioremediation of heavy metals, and mitigation of greenhouse gas emissions. This review suggests the imperative roles of R. palustris as an effective bio-fertiliser in agriculture. However, the scalability of production and application deserved more attention. The potential substrates ranging from different waste streams and formulation methods for R. palustris production are summarised to discuss environmental and economic sustainability.