Veteran leftist Luiz Inácio Lula da Silva took the oath of office on Sunday as Brazil's first democratically elected president to win three terms, with more than a dozen heads of states in attendance.
"My message today is one of hope and reconstruction," Lula said in his inaugural speech. "Democracy was the big winner of this election."
In a break from custom, his predecessor, the far-right nationalist Jair Bolsonaro, did not hand over the presidential sash to Lula, after the Bolsonaro travelled to the US state of Florida with his family on Friday.
Before the ceremony, Lula drove through the capital Brasília in an open Rolls Royce with his wife Janja and new Vice President Geraldo Alckmin and his wife. A large music festival with over 40 artists was set to follow the swearing-in.
Lula led Brazil from 2003 to 2010, at a time when his government profited from the raw materials boom and was able to lift millions of people out of poverty through major social programmes.
However, there was also widespread corruption and Lula was also sentenced to a lengthy prison term for corruption and money laundering, though the sentence was later overturned.
He beat Bolsonaro in a run-off election in October.
During Bolsonaro's term in office, relations with other countries were tense, as deforestation of the rainforest increased unchecked and the government was accused of contempt for human rights.
World powers view Brazil under Lula as a potential strategic political and economic partner. Brazil's enormous natural resources and large agricultural economy make it a big power in Latin America.
Lula has announced plans to strengthen environmental and climate protection, plus measures to combat a resurgence of hunger amid the country's economic slowdown and high inflation.
But the 77-year-old faces major challenges to achieving his inclusive agenda, first and foremost of which is Brazil's highly polarized politics. Bolsonaro's allies control both chamber of Congress.
