Kingstone takes over from Matthew Sherrington, who had been interim comms director since August 2017 when Jack Lundie left to re-join Save the Children as centenary director.
Kingstone is currently the Queen’s media secretary, a position he has held since 2016. Kingstone joined Buckingham Palace in 2013 as assistant comms secretary.
Prior jobs include fifteen years as international correspondent with BBC News. Kingstone has had extended postings in Washington, Europe and Latin America, and has covered stories for the Today Programme and Ten O'Clock News.
Oxfam has been tainted by scandal in recent months after it was revealed that aid workers sexually exploited crisis-stricken Haitians in the wake of the 2011 earthquake. The charity's lacklustre response to this earned it PRWeek's Flop of the Month accolade earlier this year.
Mark Goldring, Oxfam GB chief executive, said Kingstone would "play a crucial role in ensuring that we demonstrate to the public and our supporters that we are worthy of their trust, have learned from our mistakes and taking the steps necessary to do better in future".
"We believe that his leadership and skills will help us to communicate the real difference our work makes to millions of people every year who are striving to escape poverty or struggling to survive humanitarian crises," he continued.