The president announced that Mr Giuliani tested positive in a tweet on Sunday.
“Get better soon Rudy, we will carry on!!!” he said.
Mr Giuliani was at Georgetown University Medical Center, according to a person who was aware of his condition.
The former mayor of New York City, Mr Giuliani is the public face of the Trump campaign’s dozens of quickly unravelling legal challenges to the election. His efforts to challenge the outcome have taken him across the country – Pennsylvania, Michigan, Washington DC – in recent weeks, and he’s almost never pictured wearing a mask.
At a hearing on Wednesday before the Michigan legislature about alleged voter fraud, where the campaign has trotted out a number of unsubstantiated allegations, Mr Giuliani even asked a witness seated next to him to remove her mask. He was seated a few feet away and unmasked himself.
He has also been in close proximity to a number of people who have had confirmed cases of the virus. Mr Giuliani helped the president prepare for the first presidential debate, after which Mr Trump announced he had tested positive. In late November, the former New York mayor also appeared unmasked at a news conference at the Republican Party headquarters in Washington alongside his son Andrew, a special assistant to the president, who announced the following day he had tested positive.
It’s the latest in a string of coronavirus outbreaks that have dogged the White House. The president, alongside his chief of staff Mark Meadows, press secretary Kayleigh McEnany, campaign adviser Corey Lewandowski, and housing secretary Ben Carson have all been hit by the virus.
And just as many have criticized the US coronavirus response for failing to implement widespread testing – the president is sceptical of testing because he says it “makes us look bad” – the outbreak inside the White House has featured dubious public health responses so far.
Following an event in the Rose Garden where numerous attendees didn’t wear masks and later tested positive for the virus, the White House did not implement full contact tracing. During the president’s bout of the virus, the White House also would not publicly confirm details about when the president’s last negative test was, potentially endangering those he came in contact with.
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies