Non-perturbative solutions to the quantum-field theory is a topic of current and broad interest, especially for the heavy ion and laser physics communities, which investigate particle production in the presence of of strong external fields. We have solved a non-perturbative QED + external field problem of an electron in a strong transverse confining potential using Hamiltonian light-front quantum field theory in a basis function representation. With this method the perturbative QED result for the electron anomalous magnetic moment is reproduced with a good accuracy. We also discuss the extension of the method to other problems as well.