But the former prime minister - who quit as an MP in 2016 - won't be returning to the House of Commons.
Instead, he has been made a peer and will re-enter Parliament via the House of Lords, as Lord Cameron.
It has raised questions about how elected MPs will be able to hold him to account, including from Labour and Commons Speaker Sir Lindsay Hoyle.
All government departments tend to have ministers in the House of Lords, but normally not cabinet ministers. Until 2007, the lord chancellor was always in the Lords and a member of the cabinet too.
But more recently, there is normally only one peer who sits in the cabinet: the Leader of the House of Lords, currently Lord True.
However, it is not unheard of for other cabinet ministers to come from the upper house.
Nicky Morgan stayed on as Boris Johnson's culture secretary for several months after standing down as an MP at the 2019 election, taking the ermine and becoming Baroness Morgan in the process.
The now-Lord Cameron also had a peer in his own cabinet: Baroness Warsi, who served as Tory Party chairwoman via a peerage.
Gordon Brown gave Peter Mandelson a peerage so he could make his sensational 2008cabinet comebackas business secretary (he had quit as an MP to become the UK's European commissioner).
Mr Brown also made Lord Adonis his transport secretary in 2009 - with Lord Falconer and Baroness Amos serving in the cabinet of Sir Tony Blair.
The last UK foreign secretary to sit in the House of Lords was Lord Carrington, who took up the role under Margaret Thatcher in 1979.
He'd already been in the cabinet as a peer - he was defence secretary under Edward Heath.
He resigned as foreign secretary in 1982 after the Falkland Islands were invaded by Argentine forces, taking responsibility for the failure to predict the invasion.
Lord Cameron has confirmed he will appear before MPs on Commons select committees "as appropriate".
But he won't be in the Commons chamber to take questions during the regular departmental scrutiny sessions that take place every five weeks.
Instead, those questions will be fielded by the ministers below him at the Foreign Office, including Andrew Mitchell and Anne-Marie Trevelyan.
He also won't answer urgent questions from MPs during emergencies.
It is likely, however, he will have to respond to the equivalent version in the House of Lords - a procedure put in place for Lords Mandelson and Adonis.
In it not uncommon though for these questions to also be answered by deputies anyway, if the foreign secretary is on diplomatic visits around the world.
As a minister in the Lords, he will have to respond to written questions from peers, as well as letters from committees.
The Labour politician that Lord Cameron would normally face in the Commons, shadow foreign secretary David Lammy, has said MPswon't be able to hold him to account.
Similar reservations have also been expressed by Sir Lindsay Hoyle, the Commons Speaker, who said he would "do everything" he could to ensure Lord Cameron faces scrutiny.
This was especially important, he added, given the current series of crises around the world.
He said he'd looked forward to hearing from the government how he would be held "properly accountable" - and had asked his parliamentary officials to draw up some ideas.
David Cameron has made a return to government, with Rishi Sunak appointing him the UK's new foreign secretary.