Deputy editor Chrystia Freeland is taking Barber's former job, US managing editor, meaning she will transfer to New York and take control of the American print and online operations.
Her place in London has been taken by Martin Dickson, currently editor of the Lombard column and an FT veteran of 20 years.
Barber has also replaced news chiefs Tracy Corrigan and Deborah Hargreaves with a single news editor, Robert Shrimsley. His London-based role extends to overseeing the FT's news desks in New York and Hong Kong.
Shrimsley currently writes the daily Notebook column and has held several senior roles at the FT including UK news editor and chief political correspondent.
An FT spokeswoman said that Corrigan and Hargreaves' new roles would be revealed at a later date.
Barber took over as editor of the FT on November 3, after the departure of Andrew Gowers due to what were described as differences with the management board. Gowers has since proclaimed that his next move "won't involve ink printed on dead trees".
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