The Sony account, the largest piece of business at Fallon, has not had a dedicated senior management member running it since the agency picked up the business from Saatchi & Saatchi in November.
At WCRS, Pschorr was most recently responsible for running accounts including The Number, the company behind the new directories enquiries service 118 118, the news service CNN Europe, Heinz baby food and Toshiba Computer Systems.
Michael Wall, a founding partner at Fallon, said: "Toby has the intelligence and the determination to enable us to deliver our vision to Sony."
Pschorr began his career in 1995 at WCRS working on BMW's first global brand advertising campaign, called "The prototype - the finished article".
He managed major accounts including Vizzavi Europe and Prudential and, in December 2000, he was promoted to the board as business director.
He was also a founding member of WCRS's dedicated dotcom and technology unit.