The current cosmic acceleration can arise from small modifications to the Einstein-Hilbert action of general relativity, specifically terms of the form $ R^n $ with $ n < 0 $. This eliminates the need for dark energy, though it does not address the cosmological constant problem. The paper proposes a unified gravitational origin for both early and late-time cosmic acceleration. The model introduces a new parameter $ \mu $, leading to a modified gravitational action that can produce self-accelerating vacuum solutions. These solutions can behave like vacuum energy or lead to power-law acceleration with $ w_{DE} < -2/3 $. The model is consistent with existing gravity tests and current cosmological observations. The theory also allows for early inflation through modifications with $ n > 0 $. The model is shown to be consistent with solar system tests and other astrophysical observations. The paper concludes that cosmic acceleration can be explained purely through gravitational effects, without invoking dark energy. The model also accommodates current observational bounds on the equation of state parameter. The paper highlights that the smallness of the $ 1/R $ term in the action is directly related to the lateness of the accelerating phase. The model is generalized to other forms of the gravitational action, leading to similar late-time self-acceleration. The paper also discusses the implications of the model for the early universe and the possibility of both early and late-time cosmic acceleration arising from the gravitational sector of the theory.The current cosmic acceleration can arise from small modifications to the Einstein-Hilbert action of general relativity, specifically terms of the form $ R^n $ with $ n < 0 $. This eliminates the need for dark energy, though it does not address the cosmological constant problem. The paper proposes a unified gravitational origin for both early and late-time cosmic acceleration. The model introduces a new parameter $ \mu $, leading to a modified gravitational action that can produce self-accelerating vacuum solutions. These solutions can behave like vacuum energy or lead to power-law acceleration with $ w_{DE} < -2/3 $. The model is consistent with existing gravity tests and current cosmological observations. The theory also allows for early inflation through modifications with $ n > 0 $. The model is shown to be consistent with solar system tests and other astrophysical observations. The paper concludes that cosmic acceleration can be explained purely through gravitational effects, without invoking dark energy. The model also accommodates current observational bounds on the equation of state parameter. The paper highlights that the smallness of the $ 1/R $ term in the action is directly related to the lateness of the accelerating phase. The model is generalized to other forms of the gravitational action, leading to similar late-time self-acceleration. The paper also discusses the implications of the model for the early universe and the possibility of both early and late-time cosmic acceleration arising from the gravitational sector of the theory.