The mechanical behavior of a Zircaloy-4 sheet as induced by a pulsed laser was studied with an accurately developed computational process that was validated with experiments. A modified Gaussian model of the heat source and the use of experimentally obtained thermal and mechanical properties of Zircaloy-4 in the computational process provided reliable simulation results of the phase transition and mechanical deformation of Zircaloy-4. A parametric study of the pulsed laser welding conditions of Zircaloy-4 was undertaken using the developed computational process. The analyzed parameters were the laser power, pulse duration, and pulse frequency. The simulation results revealed that the deformation was significantly dependent on the geometry of the molten zone and the heat-affected zone, which can be designed by the analyzed laser parameters.