Brazilian President Dilma Rousseff waited on the tarmac for the pontiff to step down the stairs from the no frills commercial airliner that was specially booked for him.
It was the first time the Argentine-born Francis had returned to his home continent since his selection as pope in March.
Earlier on the flight from Rome, Francis expressed concern for a generation of youth growing up jobless as the world economy sputters.
The message should resonate with the young people in the mammoth crowds expected at a papal Mass on Rio's Copacabana beach and other ceremonies during Francis' seven days in Brazil, the world's most populous Roman Catholic nation.
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The pontiff is expected to arrive in Rio de Janeiro at 1900 GMT today.
During his flight from Rome, Francis warned about youth unemployment in some countries in the double digits, telling about 70 journalists aboard the papal plane that there is a "risk of having a generation that hasn't worked." He said, "Young people at this moment are in crisis."
"I'm here for faith! I'm here for joy! And I'm here for the first Latino pope!" Ismael Diaz, a 27-year-old pilgrim wrapped in the flag of his native Paraguay, said as he bounded down the stone sidewalks of Copacabana hours ahead of Francis' arrival.
Diaz gave high fives to four fellow pilgrims, then turned toward local beachgoers who looked back at him while calmly sipping green coconut water and staring from behind dark sunglasses.