Pope Francis has appeared at his window of the Gemelli hospital in Rome and offered a blessing for the first time since being admitted on 14 February.
The 88-year-old pontiff was discharged minutes later and doctors say he will need at least two months of rest at the Vatican.
During the past five weeks, he presented "two very critical episodes" where his "life was in danger", Dr Sergio Alfieri, one of the doctors treating the Pope, said.
Pope Francis was never intubated and always remained alert and oriented, Dr Alfieri said. Even though the Pope is not completely healed, he no longer has pneumonia and will return to work as soon as possible, if the trend continues, doctors say.
Mayor of Rome Roberto Gualtieri told the BBC he felt "a really great joy, great emotion to see Pope Francis leaving the hospital".
"It's a great gift to the city and to the world... we support him and feel really close to him," the mayor said.
APTNA crowd of people gathered outside the hospital on Sunday, waiting for the Pope to appear.
"When I saw him I felt, to be honest, a little relieved," said Bishop Larry Kulick, from the Diocese of Greensburg in the US state of Pennsylvania. "I felt just overjoyed to see him."
"I cried all the time because the love we breathe in this little square of this hospital was like heaven," said Ilaria Della Bidia, a singer from Rome.
Ana Matos from Brazil said she "just arrived from Brazil today" and arrived outside the hospital "30 seconds before he appeared". She said that "it was an amazing feeling, like when I had my son. I was so happy to see him healthy and I could see him smile".
The Pope had only previously been seen by the public once since he was admitted to hospital, in a photograph released by the Vatican last week, which showed him praying in a hospital chapel.
Earlier this month, an audio recording of Pope Francis was played in St Peter's Square in Vatican City.
His voice was breathless as he thanked the Catholic faithful for their prayers.
Pope Francis has spent 12 years as leader of the Roman Catholic Church.
He has suffered a number of health issues throughout his life, including having part of one of his lungs removed at age 21, making him more prone to infections.
Additional reporting by Giulia Tommasi
