Hall, 41, has been given the brief of championing consumer-focused research at the agency.
He joins as an executive director, with Starcom Motive's existing research and intelligence unit reporting directly to him.
Hall previously ran his own consumer research consultancy called Informer, which worked with clients such as Allied Domecq, Nike and Coca-Cola. Informer closed earlier this year. Before this, he spent time working in research at Taylor Nelson and as a client at Bayer.
Hall will work across Starcom Motive's and MediaVest's entire client portfolio on new-business briefs and will lead SIU in developing consumer insight. He said he would also work to develop deeper relationships with the creative agencies.
Hall was involved with Starcom Motive's successful media pitch for Honda in the summer. The agency shares the account with Naked, which handles strategic communications.
He said: "Having looked so long at brands from an independent consumer viewpoint it's clear to me that media is where it's at."