The influence of isotropic physical pressure, applied either during the high-pressure-high-temperature (HPHT) annealing or the measuring processes, on the magnetic properties of NdFeO single crystal, has been investigated. In comparison to the complete spin reorientation (SR) in an as-grown NdFeO single crystal, the thermomagnetic M(T) and isothermal M(H) curves for a HPHT-annealed sample indicates an incomplete SR transition from a Γ-rich to a Γ-rich Γ mixed phase. Moreover, the M(T) curves of the as-grown sample under different measuring hydrostatic pressures suggest that the SR transition takes place in the sequence of Γ→Γ +Γ +Γ→Γ +Γ→Γ, instead of the Γ→Γ +Γ→Γ, without applying pressure during the measuring process. Such manipulation of the magnetic configuration reveals that the 3d-4f interaction in the NdFeO could be greatly affected by the isotropic pressure. These findings may provide a new perspective and possibility for the tuning of the magnetism and corresponding microscopic interactions.