  In this paper we compute the spin-dependent terms of the gravitational
potential for general spinning bodies at the leading Newton's constant $G$ and
to all orders in spin. We utilize the on-shell approach, which extracts the
classical potential directly from the scattering amplitude. For spinning
particles, extra care is required due to the fact that the spin space of each
particle is independent. Once the appropriate matching procedures are applied,
taking the classical-spin limit we obtain the potential for general spinning
bodies. When the Wilson coefficients are set to unity, we successfully
reproduced the potential for the Kerr black hole. Interestingly, for finite
spins, we find that the finite-spin deviations from Kerr Wilson coefficients
cancel with that in the matching procedure, reproducing the Kerr potential
without the need for taking the classical-spin limit. Finally, we find that
when cast into the chiral basis, the spin-dependence of minimal coupling
exhibits factorization, allowing us to take the classical-spin limit straight
forwardly.
