RIO DE JANEIRO — Brazilians signaled a desire for a radical shift in the country’s course when they elected the far-right lawmaker Jair Bolsonaro as their next president in October.

It didn’t take long for profound changes to start taking hold.

In the weeks leading up to Mr. Bolsonaro’s swearing-in on Tuesday, his embrace of a conservative movement that rejects discussion of gender or sexual orientation in schools thrust classrooms to the front lines of culture wars.

Under his direction, Brazil pulled out of hosting the 2019 United Nations summit meeting on climate change and began backtracking from its role as a global exemplar of environmentally sustainable development.

And on the foreign policy front, Mr. Bolsonaro courted the United States and picked a fight with Cuba, which responded by rescinding a program that had sent Cuban doctors to remote corners of Brazil since 2013.