Prime Minister Rishi Sunak said the changes would “strengthen his team in government to deliver long-term decisions for a brighter future”.
Mr Cameron's surprise return to government comes after he stepped down as UK prime minister in 2016 following the Brexit referendum. No longer an MP, he will be made a peer to take his place in the cabinet.
The former UK Chancellor Nadhim Zahawi told The National that Mr Cameron’s appointment would have a positive impact on the current strife experienced in the Middle East. “This is a very positive decision by the Prime Minister,” he said.
“David Cameron is both highly knowledgeable and as a former prime minister he carries much weight with leaders in the Middle East. A big focus for him now will be to address the turmoil that the region is currently experiencing.”
In a post on X, formerly Twitter, Mr Cameron, now known as Lord Cameron, said the UK faced “international challenges, including the war in Ukraine and the crisis in the Middle East”.
Mr Cameron also said that while “I may have disagreed with some individual decisions” made by Mr Sunak, he “is a strong and capable Prime Minister, who is showing exemplary leadership at a difficult time”.
“At this time of profound global change, it has rarely been more important for this country to stand by our allies, strengthen our partnerships and make sure our voice is heard,” he said.
The reshuffle came as Mr Sunak sacked Suella Braverman as home secretary, after her comments ahead of a pro-Palestine march in central London on Saturday.
Critics accused her of fuelling tensions between police and demonstrators and “emboldening” far-right protesters, some of whom were arrested after clashes with police near the Cenotaph.
Ms Braverman's replacement Mr Cleverly is an old ally of Boris Johnson and was a staunch backer of Liz Truss before her short-lived stint in No 10.
Ms Truss rewarded Mr Cleverly by making him foreign secretary, with Mr Sunak reappointing him in October 2022.
Mr Cleverly said his goal now was to “keep people in this country safe”.
“It is an honour to be appointed as Home Secretary,” he tweeted. “The goal is clear. My job is to keep people in this country safe.”
Mr Cameron will face a more complex and unstable world on his return to government as Foreign Secretary, the most pressing of which is the Israel-Gaza war, which could still escalate into a regional conflict.
Charlotte Leslie, the director of the influential Conservative Middle East Council, said Mr Cameron’s appointment came at a “crucial time” for the region with someone who understood the complex issues.
“David Cameron is an astute appointment,” she told The National. “His predecessor, James Cleverly, as the new home secretary has a strong understanding of the regional issues currently being felt domestically, and David Cameron takes on the role as a very experienced, respected politician, bringing long-standing trusted relationships to the table at a crucial time.”
Former prime minister Theresa May, who served as home secretary in Mr Cameron’s government, said the former Conservative leader’s experience on the international stage “will be invaluable” in his role as Foreign Secretary.
As recently as Thursday, Mr Cleverly was in Saudi Arabia discussing efforts to prevent escalation with Middle Eastern foreign ministers, and Mr Cameron will face the immediate task of carrying on that diplomatic effort.
Mr Cameron will not face the regular sessions of Foreign Office questions, with more junior ministers instead fielding questions in the Commons chamber.
Shadow foreign secretary David Lammy criticised the situation, which will also mean that major statements are either made first in the Upper Chamber by Lord Cameron or by a less senior minister in the Commons.
Mr Lammy said that during an “international crisis”, Rishi Sunak “has chosen an unelected failure from the past who MPs cannot even hold to account”.
Mr Cameron is now the 15th former prime minister to serve in a later government led by someone else, according to a UK government blog from November 2012.
Sir Alec Douglas-Home, who served for just under a year as prime minister after taking office in October 1963, was later appointed foreign secretary by Edward Heath.
He held the role from 1970 until 1974 and is the last former PM to return to government under a different leader.
With the autumn statement due next week, Chancellor Jeremy Hunt remains in his post.
He has been under pressure from some Tory MPs to offer tax cuts in the build-up to the general election expected next year but has prioritised efforts to cut inflation.
Meanwhile, Mr Sunak promoted roads and local transport minister Richard Holden to Tory chairman, replacing Greg Hands in the key role at party headquarters.
In the junior ranks, Will Quince and Neil O’Brien both quit as health ministers, while veteran schools minister Nick Gibb also left his post, Jesse Norman departed from the Department for Transport and Rachel Maclean was sacked as housing minister.
Therese Coffey also resigned as environment secretary, saying it that it was “now the right time to step back from government” in a letter to the Prime Minister.
Steve Barclay will step down as health secretary to take the role, Downing Street announced. Victoria Atkins will be the new Health Secretary.