Cardinal Prevost will be known by the name Pope Leo XIV and is the first American and first native English-speaker to be appointed to the lead the faith.
Brisbane Archbishop Mark Coleridge said he had been impressed during their previous meetings and always thought the Chicago native was a "rough chance" to become Pope.
"But I was surprised when I woke early to the news of his election as Pope Leo XIV - I was also delighted," he said.
Archbishop Coleridge said despite a rapid rise Pope Leo wasn't a man to "rush things" and had an air of calm that would serve him well in his new role.
"He struck me as a man who ... was hard to fluster, a good driver in heavy traffic ... he will be his own man," he said.
Melbourne Archbishop Peter Andrew Comensoli had also met Pope Leo several times, saying he was a "great listener" with "wide experience and great depth of faith".
"Clearly the cardinals were confident that they chose Cardinal Prevost," Archbishop Comensoli told AAP.
"It's great news. We have a chief shepherd and we will all look forward to getting a sense of him, as he begins his ministry."
The Chicago native's "missionary heart" would hold him in good stead, Sydney Archbishop Anthony Fisher said.
"Like the late Pope Francis, Pope Leo XIV will bring to the church the experience of being part of a religious order with an emphasis on simplicity and community," he said.
"It was very moving that the Holy Father opened his first address to a watching world with a greeting of peace, and repeated the central truth of the gospel, that God loves all of us 'without any limits or conditions'."
Leo spent decades as a missionary in Peru, before Pope Francis appointed him to lead the Vatican's bishop selection process.
Archbishop Fisher, along with Prime Minister Anthony Albanese, invited Leo to the International Eucharistic Congress, to be hosted in Sydney in 2028.
Mr Albanese said the appointment brought joy and hope to Catholics everywhere.
"May the papacy of Pope Leo advance the cause of peace and social justice for all humanity," he said.
Australian Catholic Bishops Conference president Archbishop Timothy Costelloe offered the Catholic church in Australia's heartfelt congratulations.
"Cardinal Prevost brought to his most recent role as Prefect of the Dicastery for Bishops an approachability and willingness to listen which were no doubt developed throughout his many years as an Augustinian missionary in Peru," he said.
Catholic Social Services Australia executive director Jerry Nockles said Pope Leo's appointment came at a critical time when the world yearned for compassionate leadership grounded in gospel values of justice, dignity and solidarity with the vulnerable.
"Pope Leo's election offers a beacon of hope and a powerful reminder that the church stands firmly for peace and with those on the margins," Dr Nockles said.
Cardinal Mykola Bychok was the sole Australian representative at the conclave in Rome.
Archbishop Costelloe and Sale Bishop Greg Bennet have indicated they will travel to Rome for the installation representing the Australian Catholic Bishops Conference and the church in Australia.
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