The accelerating expansion of the universe, attributed to dark energy comprising approximately 68% of the cosmos, remains one of the most significant unsolved problems in modern physics. We present a synthesis of two established theoretical frameworks (the holographic principle and horizon thermodynamics) identifying the universe's holographic boundary with a black hole event horizon. This identification is grounded in Gibbons and Hawking's proof that cosmological horizons possess thermodynamic properties identical in form to black hole horizons, combined with five decades of black hole cosmology models demonstrating mathematical consistency of universe-in-black-hole scenarios. Under this framework, universal expansion corresponds to matter accretion as perceived from the horizon surface, and accelerating expansion emerges from the feedback dynamics of black hole growth, requiring no exotic energy component. This synthesis preserves all predictions of standard cosmology while eliminating dark energy as a fundamental constituent, deriving cosmic acceleration from established gravitational and thermodynamic physics. Corresponding author: bmichaelyates@gmail.com