Ms Gray missed Labour's first party conference in power as the prime minister attracted scrutiny for the more than £100,000 worth of gifts he accepted as Labour leader, including tickets to football matches, concerts and luxury clothes.
Sir Keir Starmer's former chief of staff Sue Gray has taken up her place in the House of Lords after she was nominated by the prime minister for a peerage.
In her resignation letter last October, Ms Gray said that while it had been "an honour to take on the role of chief of staff", it had become clear that "intense commentary around my position risked becoming a distraction to the government's vital work of change".
Baroness Gray was later offered the role of the prime minister's envoy for the nations and regions, which she ultimately rejected after missing the first key summit relevant to her new remit.
Ms Gray was among 30 new Labour peerages announced ahead of Christmas to redress the party "imbalance" in the House of Lords.
