The 39-year-old enjoyed a hugely successful campaign at the helm of Sporting Lisbon last term, guiding them to second in the Primeira Liga and securing a return to the Champions League for the first time since 2008-09.
However, Sporting revealed last month that a €3 million release clause in his contract had been triggered, allowing him to leave.
And Jardim is delighted to have made the switch to the Stade Louis II.
"I am very happy to work for Monaco as it is a big club," he told the club's official website.
"I fully believe in this project and I think that this group can go far.
"AS Monaco is a team with players full of quality. There are many young players with a lot of talent.
"I am going to do everything to help them progress. The first thing is to start learning to speak French.
"I have been taking lessons for a few days now, it is question of respect towards the supporters, and the people of Ligue 1."
The seven-time French champions have spent big since Dmitry Rybolovlev's takeover in 2011, splashing out on star names such as Joao Moutinho, James Rodriguez and Radamel Falcao.
