Roula Khalaf only found out she had made history by becoming the Financial Times' first female editor the night before the news was revealed to the rest of the paper.
Ms Khalaf said she was "thrilled to be appointed" the editor of "the greatest news organisation in the world", following the decision of long-serving editor Lionel Barber to stand down after 14 years.
The outgoing editor - the longest-serving national newspaper editor in the country - said "it has been a rare privilege and great pleasure to hold the best job in journalism."
Mr Barber announced he would stand down in the New Year and will be replaced by current deputy Roula Khalaf as editor.
She told the FT newsroom on Tuesday morning: "I only learned of my good fortune last night."
Ms Khalaf has the support of leading figures at the paper, including assistant editor Janine Gibson, who tweeted it was "brilliant news."
After a 131-year history, Ms Khalaf will become the paper's first female editor.
She has been the FT's deputy editor since 2016, but has been part of the paper for 24 years.
Ms Khalaf was previously the FT's foreign editor responsible for leading a global network of more than 100 correspondents and pushing for greater diversity in the newsroom.
During that time, she has launched Trade Secrets, described as “a new content vertical focused on global trade” and concentrated on winning over more women readers.
Recent investigations have looked particularly at the behaviour of senior men in business, including an undercover report from the President’s Club Ball and allegations of wrongdoing by the founder of cloud business UKFast, Lawrence Jones.
Tsuneo Kita, chairman of Nikkei, which owns the FT, said: “I have full confidence that she will continue the FT’s mission to deliver quality journalism without fear and without favour, inspire and lead a team of the most talented journalists and pursue the FT’s new agenda covering business, finance, economics and world affairs.
“Roula’s 24-year FT career, including her tenure as deputy editor, has proven her integrity, determination and sound judgment."
Ms Khalaf said: “It’s a great honour to be appointed editor of the FT, the greatest news organisation in the world.
“I’m thrilled to be leading the most talented newsroom through the next chapter of FT excellence. I look forward to building on Lionel Barber’s extraordinary achievements and am grateful for his mentorship through the years.”
Ms Khalaf has also been the Middle East editor during the Arab Spring, and has worked in North Africa
The FT has a huge following in the City, with business leaders keen to appear in its pages.
However, the newspaper has a strong union presence and has fought in recent years for tougher regulation on the City and an improvement in working conditions at companies – particularly for women and minorities.
It has also been avowedly pro-EU in its coverage of the Brexit uncertainty – reflecting the views of the majority of businesses it covers.
Outgoing editor Mr Barber was offered France’s highest honour, the Legion d’Honneur, in recognition of his career in journalism and the paper’s “positive role in the European debate”.
He was also a firm fixture on the pundit scene, taking part in several discussions and debates on the biggest issues facing UK and international businesses.