Freeland, 34, is currently editor of the Saturday edition of the FT. She will take up her new role in July, when Ridding moves to Hong Kong to become editor and publisher of the planned Financial Times Asia.
Freeland, a Canadian, joined the Financial Times in 1994 and has held the roles of Eastern Europe correspondent, Moscow bureau chief and UK News editor before returning home to Canada to become deputy editor of The Globe & Mail.
She returned to the FT in October 2001 as editor of FT.com and was responsible for the successful launch of subscription services in May 2002. Freeland is a Rhodes Scholar and a graduate of Harvard.
Freeland is replaced as editor of the Saturday FT by Richard Addis, the former Daily Express editor. Addis is currently design editor at the FT and will retain his design brief in addition to his new role.
Following John Gapper's appointment as chief business commentator and associate editor, Andrew Hill succeeds him as comment and analysis editor. He will move back to London from New York, where he is currently New York bureau chief.
Andrew Gowers, editor of the Financial Times, said: "Chrystia Freeland is one of the most talented journalists of her generation. She has an uncanny strategic sense, combined with an incredible ability to get things done, and I'm delighted to appoint her as deputy editor."
He added: "Richard Addis is ideally placed to take the baton from Chrystia as editor of the Saturday edition. He was a key player in driving the changes we've made to the daily and Saturday editions and has done an outstanding job in his role as design editor."
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