A gas turbine engine component includes a wall portion with at least one compound cooling hole formed therein between an external surface of the component and an interior plenum. The at least one compound cooling hole includes a non-circular diffuser opening formed by a laser beam with a non-circular cross-sectional area, and a channel with a substantially circular cross-section connecting the diffuser opening and the interior plenum. The channel is also formed by the non-circular laser beam in the same laser drilling operation as the diffuser opening. The cooling hole further includes a transition point at which the compound hole begins to convert from a substantially non-circular cross-section to a substantially circular cross-section. The location of the transition point is controlled by positioning a focal point of the non-circular laser beam to undershoot the external surface of the component by a predetermined distance.