Far-right Mr Bolsonaro is a favourite among Latin American voters according to polls published the day before ballots opened today and 147 million Brazilians flocked to stations to cast their votes.
The 67-year-old said: “Let’s make Brazil Great! Let’s be proud of our homeland once again!
“Together we are going to change Brazil!”
The proclamation saw the politician gain a huge lead over his closest rival, the Workers’ party (PT) candidate Fernando Haddad.
The Brazilian Institute of Public Opinion and Statistics (Ibope) poll showed 32 percent of voters were prepared to support Mr Bolsonaro, while Mr Haddad came in at around 23 percent.
Glauco Peres, a political scientist from the University of São Paulo, explained poll results showed it would not be enough to avoid a second-round showdown between far-left Mr Haddad and anti-establishment Mr Bolsonaro.
He said: “It is unlikely that this election will be decided in the first-round.
“Everything here has been so unpredictable that I don’t know if I’ll put my neck on the line for anything anymore.”
Despite having more than seven million Facebook followers and obtaining a surge in support from voters in Brazil, the prospect of Mr Bolsonaro winning the general election has horrified minorities backed by celebrities such as Cher and Madonna.
Mr Bolsonaro, who heads the Social Liberal Party, was once quoted in 2002 discussing his hate for homosexual people.
He told an interviewer: “If I see two men kissing each other in the street, I’ll whack them.”
Nine years after, he said: “I’d rather my son died in an accident than showed up with some bloke with a moustache.”
Ciro Gomes, the Democratic Labour party candidate at third place with 15 percent of the votes according to the polls, said Brazil was “walking towards a precipice”.
Marina Silva, the fifth-placed Sustainability Network party candidate, added: “Brazil is on the verge of an irreversible rupture.”
But Mr Bolsonaro’s followers believe he will lead Brazil out of their worst ever recession.
Supporter Paulo Henrique Villa Boas said: “Bolsonaro is Brazil’s only option right now if it wants to avoid becoming a Venezuela.”