The PlayStation Vita was a collaborative effort by hundreds of engineers and designers at Sony Computer Entertainment (later Sony Interactive Entertainment). No single person "designed" it, but key leadership included:
Hardware (SCEI Platform Engineering), Software (OS, SDK, Tools), Services (PSN, Store, Trophies), Design (Industrial, UI, Packaging), Developer Relations (DevNet, PhyreEngine), QA, Manufacturing (Foxconn, Pegatron).
The Vita's unique features—rear touchpad, dual analog, OLED (launch), 3G model, AR cards, cross-play—required unprecedented cross-discipline coordination.