Henry has signed a deal until June 2021 and left his role as Belgium's assistant manager to take up the job at the club he started his professional football career with.
The former Arsenal striker helped Monaco win the Ligue 1 title in 1997 and takes over with the side third from bottom in the French top flight this season.
In his first meeting with the press Henry talked up the influence Guardiola had on his insight to the tactical side of football during their time at FC Barcelona.
The France all-time record scorer won two La Liga titles and the Champions League with Pep.
"There's no right or wrong; that's the reference for me," he said of his intention to emulate Guardiola's tactical philosophy, as quoted by the club's website.
"I re-learned how to play the game when I went to Barcelona under him.
"With Pep you can talk about the game; he will not even go to sleep and will still talk about the game, you will fall asleep and he's still talking.
"You learn from people; they inspire you. But you also need to put your own little mix in it."
Asked about fellow Frenchman Arsene Wenger, under whom he is considered to have played his best club football with Arsenal in his first spell in north London from 1999 to 2007.
Henry said: "Arsene unlocked a lot of stuff in my mind, made me understand what it was to be a professional, what it was to perform.
"I will never forget that. You know the relationship I had with him so I will always carry some of the stuff that he was doing."
Henry's first game in charge will be against Strasbourg in the league on 20 October, before a Champions League tie with Club Brugge four days later.