We derive mass, gravity, and nuclear confinement from first principles through a spacetime mechanism where electromagnetic quantum vacuum fluctuations—originally derived from black-body radiation—induce metric perturbations that serve as a foundational source. Utilizing correlation functions, we demonstrate that highly coherent modes of zero-temperature black-body radiation undergo decoherence within the proton’s resonant cavity, producing its exact mass energy density. From Einstein’s field equations, we calculate the conversion factor of electromagnetic vacuum fluctuations into gravitational waves traveling through the proton’s cavity. We find that this converted energy is equivalent to the energy density of a Kerr-Newman solution at the proton’s reduced Compton wavelength, which defines a surface horizon. We compute the Hawking radiation and evaporation of this surface and find it equivalent to the proton’s rest mass. The evaporation lifetime far exceeds the observable universe’s age and satisfies experimental constraints. However, internal vacuum fluctuations within the proton cavity may provide a stabilizing source term equivalent to Hawking radiation energy, potentially affording extreme stability to the proton. Our formulation reduces to a Klein-Gordon equation on the metric perturbation that yields a confining Yukawa-like energy potential, demonstrating that both confining forces and gravitational forces emerge as consequences of metric perturbations generated by quantum electromagnetic fluctuations. This result aligns well with experimental measurements across multiple scales—from the color force to the residual strong force, and ultimately to gravitation. By computing both confining forces and gravity as emergent manifestations of vacuum fluctuations curving spacetime rather than separate fundamental interactions, we resolve Einstein and Rosen’s attempt to geometrize particles and forces at the quantum scale.