  The Kepler supernova remnant (SNR) is the only historic supernova remnant
lacking a detection at GeV and TeV energies which probe particle acceleration.
A recent analysis of Fermi-LAT data reported a likely GeV gamma-ray candidate
in the direction of the SNR. Using approximately the same dataset but with an
optimized analysis configuration, we confirm the gamma-ray candidate to a solid
$>6\sigma$ detection and report a spectral index of $2.14 \pm 0.12_{\rm stat}
\pm 0.15_{\rm syst}$ for an energy flux above 100 MeV of $(3.1 \pm 0.6_{\rm
stat} \pm 0.3_{\rm syst}) \times 10^{-12}$ erg~cm$^{-2}$~s$^{-1}$. The
gamma-ray excess is not significantly extended and is fully compatible with the
radio, infrared or X-ray spatial distribution of the SNR. We successfully
characterized this multi-wavelength emission with a model in which accelerated
particles interact with the dense circumstellar material in the North-West
portion of the SNR and radiate GeV gamma-rays through $\pi^{o}$ decay. The
X-ray synchrotron and inverse-Compton (IC) emission mostly stem from the fast
shocks in the southern regions with a magnetic field B$\sim$100 $\mu$G or
higher. Depending on the exact magnetic field amplitude, the TeV emission could
arise from either the South region (IC dominated) or the interaction region
($\pi^{o}$ decay dominated).
