Stoltenberg tweeted Thursday, expressing his gratitude to NATO leaders for extending his term until Sept. 30, 2023.
He said that "As the largest security crisis in a generation" and he stood united to keep his alliance strong and his people safe. This was after Joe Biden, U.S. President, and his counterparts, agreed to extend Joe's term at a summit held in Brussels.
In October 2014, NATO's highest civilian position was awarded to the former Norwegian prime minister. His term of office was extended for the second consecutive time. His mandate was to expire in September.
Biden tweeted that Stoltenberg had "done an extraordinary job leading and strengthening the Alliance -- especially during this crucial moment for international security."
Norway's government named Stoltenberg head of the central bank in Scandinavia in February. It stated that it hoped Stoltenberg would start his new job around Dec. 1.
Oslo Finance Minister Trygve Skavold Vedum confirmed the resignation of Stoltenberg. In his place, temporary governor Ida Wolden Bache was nominated and is expected to be confirmed on Thursday.
"Officially, I would love to see Jens Stoltenberg be our next central bank Governor. However, we are in a very difficult situation in Europe. I have great understanding of his priority in continuing in the important NATO role that he plays," Slagsvold Vedum stated.
Stoltenberg (63) has called Russia's war against Ukraine "the most serious security crisis we have ever been in for decades."
Stoltenberg was praised for leading NATO through a turbulent period of Trump's administration. The Trump administration threatened to withdraw support from member countries that were not spending enough defense funds.
Jake Sullivan, U.S. National Security Advisor, stated that Biden and Stoltenberg had "developed a trust relationship" while speaking to journalists on Wednesday's Air Force One flight from Washington to Brussels.
"Secretary General Stoltenberg played an instrumental part in helping to secure the strong unity you've seen at NATO during this crisis," Sullivan stated.
Stoltenberg served twice as prime minister of Norway, from 2000 to 2001, and again from 2005-2013. He also served as finance minister and industry and energy minister.
Norwegian Prime Minister Jonas Gahr Store stated to NTB, Norwegian news agency NTB, that Stoltenberg had done a "solid job" as NATO chief. "Never has the alliance been stronger and unity has never been more important in its history."
Wolden Bache, the central bank chief, was to be officially re-elected for a six year term on Thursday.
She said that Norway Bank had great respect for Stoltenberg's decision in light of his important responsibilities as Secretary General NATO.
Before Thursday's announcement speculation was rife about a woman being named to the top of the largest security organization in the world.