Precise finishing of the poppet valve profile will make it perfectly fit on its seat in the aerospace gas propulsion engine to reduce hydrocarbon emissions. Nano-finishing of poppet valve narrow profiles is a particularly challenging job. This article reports on the uniform polishing of the poppet profiles using a novel magnet fixture used in the rotational-magnetorheological fluid-based finishing (R-MRFF) method. The precise finishing of the Nickel aluminium bronze (BS1400 Gr. AB2) (excellent corrosion resistance and bearing properties) poppet profiles is done through various compositions of magnetorheological polishing (MRP) fluid. After performing the experiments, surface characterization and material compositions are outlined for both polished and unpolished poppet profiles. Magnetostatic simulation is also performed to observe the distribution of magnetic flux density along poppet valve profiles. This magnetostatic analysis will help in understanding the finishing mechanism properly. Ultrafine surface roughness (Ra = 21.3 nm) at poppet profiles are obtained using an MRP fluid of Type ‒ 2. All manufacturing defects are almost removed from the poppet valve profiles.