This paper presents a method for achieving planar multi-phase, multi-contact robotic walking using human inspired control and optimization. The walking presented contains phases with differing degrees of actuation including over-actuated double support, fully-actuated single support, and under-actuated single support via heel lift. An optimization methodology for generating walking gaits using partial hybrid zero dynamics will be presented. It will be shown that this method yields periodic, multi-contact locomotion. Simulation results for the three domain walking under standard Input-Output Linearization control will be presented.