Biofuels are considered as one of the best viable and inexhaustible alternatives to conventional diesel fuel. Alcohols have become very important and popular in the present scenario due to their peculiar fuel properties and production nature. This study examines the effect of n-amyl alcohol and exhaust gas recirculation of 10% and 20% on various engine characteristics of common rail direct injection (CRDI) compression ignition engine. The proportion of n-amyl alcohol varies from 5% to 25% in 5% step (by volume). The obtained results show that diesel/n-amyl alcohol blends decrease the mean gas temperature and cylinder pressure, which is 1.88% and 4.25% less at 75% load for n-amyl alcohol (25%) with conventional diesel fuel. The duration of combustion has shown a hike of 4.66 °CA for 25% n-amyl alcohol (at 75% load) compared to conventional diesel fuel. However, the cumulative heat release rate improved by 12.95% higher for 25% n-amyl alcohol at 75% load due to the extended delay in ignition. While n-amyl alcohol was used, the emission of nitrogen oxide emissions decreased considerably. However, the hydrocarbon (HC) (7–9%) and carbon monoxide (CO) (6–8%) emissions are increased due to inferior fuel properties like high latent heat evaporation of n-amyl alcohol. Compared with other blends, n-amyl alcohol (5%) produced results comparable to conventional diesel fuel, which is 3.6% higher in BSFC, 2.37% higher BTE, and 33.33% higher CO emissions 18.18% more in HC emission, and 17.55% less NOx emission. Without further modification, we can use 25% n-amyl alcohol in the combustion ignition engines. From this evidence, we can summarize that n-amyl alcohol is a biofuel that is both renewable and sustainable, and also it considerably reduces harmful nitrogen oxide emissions. The performance, if needed, can be improved by changing the parameters of the engine.