The former army captain – whose rise to prominence has been marked by divisive rhetoric and derogatory remarks about women, gay people and ethnic minorities – was inaugurated in the capital Brasilia on New Year’s Day.
He has promised a crackdown on corruption, drugs and violent crime that saw 63,000 people killed in Brazil last year, as well as close alignment with the US and business-friendly economic policies.
The 63-year-old – who has been dubbed the “Trump of the Tropics” because of his views – said in his address that his country had been “liberated from socialism and political correctness” now that he had taken power.
He told Brazil’s 210 million people that “we have a great nation to rebuild” and promised that he had put together a talented team of ministers to do just that.
Following the ceremony on Tuesday, Mr Bolsonaro received well wishes from his US counterpart, who tweeted that he had delivered “a great inauguration speech”.
Mr Bolsonaro waved to crowds of supporters draped in Brazilian flags as he made his way to the presidential palace in an open-top Rolls-Royce, alongside his wife Michelle.
Mr Trump tagged the Brazilian in his message, which ended: “The USA is with you!”
Responding in a tweet that has been pinned to the top of his account, Mr Bolsonaro said: “I truly appreciate your words of encouragement. Together, under God’s protection, we shall bring prosperity and progress to our people!”
Three years prior, he said he would “rather his son die in a car accident than be gay”.
Mr Bolsonaro has also said he is “in favour” of torture, has appeared to advocate the sterilisation of poor people, and is an outspoken supporter of the military regime that led Brazil from 1964 to 1985.