Markets reacted positively to the victory by the business-world favorite, who will take office on January 1.
Supporters flooded the streets outside Bolsonaro's home in Rio de Janeiro, letting off fireworks and waving Brazilian flags.
Here are three things to know about the candidates and their proposals:
Trailing leftist candidate Fernando Haddad accused the far-right frontrunner, Jair Bolsonaro, of 'illegal' electoral tactics.
Bolsonaro, an ultraconservative former paratrooper, easily beat a dozen other candidates on Sunday -- but not by enough to avoid an October 28 showdown with Haddad, the former mayor of Sao Paulo.