Scolari, who led Brazil to their fifth and last world title in 2002, was officially presented as coach of the 2014 World Cup hosts, while Carlos Alberto Parreira, in charge when they won their fourth World Cup in 1994, was named technical director.
"We have the obligation to win the title; we are not favourites at the moment but we intend to become favourites during the competition," said the man known as Felipao (Big Phil). "Third or fourth place is no good for a country that has won five World Cups."
The unveiling comes two days before the draw for the next year's Confederations Cup, also to be hosted in Brazil, in Sao Paulo. Scolari's first game in charge is scheduled to be a friendly away to England in February.
Brazil's vast and fickle army of supporters always expect them to win the World Cup and the pressure will be even greater as the country hosts the event.
Scolari said it was water off a duck's back. "If you don't like pressure, it's better to go and work in the Bank of Brazil, or outside on the corner or sit in an office and do nothing," he said.
"It would not be right if there was no pressure and the players thought the target was just to play at the World Cup.
"This would be one of our most important titles - the sixth title, at home at our second opportunity."
Scolari said he felt under much greater pressure when he took over for the first time in 2001 when Brazil were in danger of missing out on the following year's World Cup.
"It would have been the first time that Brazil would have missed a World Cup, that was when I felt under pressure," he said.
"I feel like a young boy, starting all over again," said Parreira, who also coached Brazil at the 2006 World Cup when they reached the quarter-finals.
"The Brazil team does you good, all that adrenalin. It's a marvellous challenge, to come back to the team for a World Cup here in Brazil, you can't describe it."
"We revolutionised the relationship with the supporters," said Scolari. "I maybe didn't win anything but the work we did was worth more than 10 or 20 titles."
"We have won all of our titles with Brazilian coaches who have taken their knowledge beyond these frontiers," he said. "Our country has a great number of competent coaches who deserve to hold this position."
