Chancellor Rachel Reeves, who sat next to Sir Keir on the front bench as usual, appeared close to tears.
Labor MP Carolyn Harris was also overcome with emotion as she told MPs that “every day we see his integrity and his courage shine through.”
Sir Keir is due to hand over power to Andy Burnham on Monday after the former Greater Manchester mayor is confirmed as Labor leader at a special Labor conference on Friday.
Conservative leader Kemi Badenoch refrained from attacking the outgoing prime minister’s record, instead praising him for his work in Ukraine and his friendship with the country’s President Volodymyr Zelensky.
But she did have a laugh at Labor MPs and their next leader, who was absent from the meeting as he has been to all of the Prime Minister’s meetings since returning to Parliament last month.
Liberal Democrat leader Sir Ed Davey said Sir Keir worked with the people in the House of Commons and called him a “true patriot”.
Several of the Prime Minister’s guests watched the proceedings, including campaigners he met during his time in Downing Street.
During the speech he addressed some of them directly, saying: “To everyone in the gallery whose lives have been changed or improved by this Labor government, and across the country who are struggling to be seen or heard, you are the reason I came into politics.”
Despite being ousted by his own MPs just two years after a landslide election victory, Sir Keir was greeted with applause from Labor members when he arrived in the House of Commons.
As is often the case at the Prime Minister’s last meeting, the tone was softer and more light-hearted than usual, with plenty of jokes about England’s World Cup hopes as well as the Clacton by-election.
However, things started on a somber note as Sir Keir paid tribute to former MP Anne Widdecombe.
He said he was “frightened” by the fact that three current or former MPs had been killed during his time in parliament.
Badenoch paid tribute to the former Conservative minister as a woman of “high principles” with a “wicked sense of humour”.