Background: Most of the heavier p isotopes are believed to be produced in the γ process whose reaction path crucially depends on the proton and α-particle penetrability at sub-Coulomb energies. Both nuclei of the samarium p-process chronometer, Sm146 and Sm144, are produced in the γ process, and their initial abundance ratio is very sensitive to the (γ,n) and (γ,α) branching ratio on Gd148. The Gd148(γ,α)Sm144 reaction rate was measured roughly 20 years ago by means of the activation technique and its surprising results triggered adjustments to the global low-energy α+nucleus optical-model potentials (OMPs). Purpose: We want to take advantage of modern α-particle spectroscopy techniques in order to constrain the controversial previous results on the Gd148(γ,α)Sm144 reaction rate. Method: The Gd148(γ,α)Sm144 reaction rate has been determined by measuring the cross section of the reverse reaction Sm144(α,γ)Gd148, applying the activation technique to the α decay of Gd148. Targets have been irradiated at the cyclotron of the Physikalisch-Technische Bundesanstalt in Braunschweig, Germany. The α-particle spectroscopy has been carried out with a state-of-the-art low-background ionization chamber of the Technische Universität Dresden, Germany. Results: Cross sections for the Sm144(α,γ)Gd148 reaction have been measured between 10.66 and 12.66 MeV with much higher precision than in the previous measurement. The results agree with earlier results within their uncertainties. The statistical-model analysis has been carried out using the talys code on the basis of the latest parametrizations of α-OMPs. The best reproductions of the experimental results within the statistical model have been used to calculate the reaction rates. Conclusion: The values presented here suggest a steeper increase in the astrophysical S factor towards lower center-of-mass energies. Different parametrizations of the α-OMP were able to describe the experimental values sufficiently. Further measurements at energies below 11.0 MeV are suggested.