Kovac replaced Robert Moreno as coach this week after Monaco finished ninth in Ligue 1 in 2019-2020.
After winning the league in 2016-2017, Monaco finished second the following season before narrowly avoiding relegation in 2018-2019.
Former Bayern Munich coach Kovac said he wanted to return Monaco back to the top.
"It was a surprise, it went very quick, so that's the reason why I'm only talking in English and not in French," he told a news conference.
"The reason is very easy. AS Monaco is a big, big club, with big tradition and the last years weren't so successful like they hope here.
"Our goal, our aim, is to bring back AS Monaco to the top of Ligue 1."
His arrival at Monaco sees Kovac return to coaching for the first time since leaving Bayern in November last year.
The Croatian said he would need to adapt his approach at Monaco, who are scheduled to begin their Ligue 1 campaign against Reims on August 23.
"Every coach has his own philosophy, his own thinking about football," Kovac said.
"In the past I played, or worked, in clubs like [Eintracht] Frankfurt or Bayern Munich. It's a different style in Frankfurt, it's another team in Munich.
"We have to adapt, we have to see, we have to take an overview of the team or the players, then we can choose the right tactics we think can help the team."