A ranar 7 ga watan Nuwamba, Williams ta tabbatar da cewa Nakajima zai zama abokin tarayya Rosberg a ƙungiyar Williams don kakar 2008. Ya yi nasarar farawa a 2008 a Grand Prix na Ostiraliya, ya gama na bakwai amma ya koma na shida bayan an cire Rubens Barrichello, duk da cewa ya fitar da Robert Kubica daga tseren kuma an hukunta shi. Daga nan ya gama na bakwai a Grand Prix na Spain, bayan ya wuce abokin aikinsa. Wani abin da ya faru da Giancarlo Fisichella a Istanbul ya tilasta masa yin ritaya. Nakajima ya ci maki biyu a
Monaco inda babu wani direban Formula One na Japan da ya taba cin kwallo, kuma ya yi ritaya daga gasar Grand Prix ta Kanada ta 2008 bayan ya buga bangon rami lokacin da yake yin sabon fuka-fukan gaba. Nakajima ya sami wata aya a gasar Grand Prix ta Burtaniya ta 2008, bayan ya rasa matsayi na bakwai a zagaye na ƙarshe. A Singapore, Nakajima ya kai zagaye na uku na neman shiga gasar a karo na farko inda ya cancanci zama na 10 a grid. Ya ci gaba da kammala na takwas kuma ya zira kwallaye.