Gallate's 19-year career at the Havas-owned network has seen him work in Australia, Singapore and New York. The new role puts him in charge of the network's activities in 18 countries.
He succeeds Vincent Digonnet, who has decided to return to Europe after seven years in the job. It is not known whether he is taking another role at Euro RSCG.
Jim Heekin, chairman and chief executive of Euro RSCG Worldwide, said: "George has played a key role in building our integrated and interactive marketing operations into a global powerhouse. His extensive experience in Asia-Pacific and dynamism will serve us well as we continue to capitalise on the explosive growth in the years ahead across this region."
Gallate was global chief executive for six years of Euro RSCG Interaction, the forerunner to Euro RSCG 4D, which he helped form in 2004. He has also served as jury president of the Cyber Lions at Cannes.
"I am excited about returning to Asia and working with our highly talented professionals and our blue-chip roster of clients," Gallate said.
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