The 23-year-old has signed a five-year contract with the Ligue 1 side for a fee reported to be close to €10 million.
And the centre-back is delighted to join the French club and is targeting Champions League qualification.
"I am very proud to sign for AS Monaco," he told the club's official website.
"This is a big club where a lot of great players have come through, and I'll be doing all I can to be one of them.
"I want to help the team achieve its objectives as quickly as possible, especially Champions League qualification. I intend to give my all for the AS Monaco shirt."
Monaco CEO Vadim Vasilyev added: "We are very proud to welcome Jemerson, a young Brazilian defender whom we have been tracking regularly.
"We have a lot of faith in him. He will have the opportunity to develop at AS Monaco, and we are sure he will soon be showing all of his qualities."
Jemerson, who earned his first call-up to the senior Brazil squad last November, spent six years with Atletico Mineiro after joining from Confianca.