The Italian coach could not hide his delight after guiding the Rouge-et-blanc back to the top tier of French football after a two-year absence from the country's top table
Ibrahima Toure scored in the fifth minute of injury-time to earn ASM a 1-0 win at Stade de Costieres and give them an unassailable 10-point lead over Angers in fourth.
The Rouge-et-blanc were widely expected to take one of Ligue 2's top three places and return to the top flight but Ranieri nevertheless stressed that his team deserve a great deal of credit.
"This promotion is a great achievement," the 61-year-old Italian was quoted by le10sport.com.
"I am very happy. It was our goal since the beginning of the championship. You may remember my first interview I said I came to win. It was the goal of the club, the president and myself, and we put this idea in the minds of players who have managed to implement it on the field."
Monaco were bought by Russian oligarch Dmitry Rybolovlev in December 2011 and have been linked with a move for Radamel Falcao in recent weeks as they look to mount a challenge against Paris Saint-Germain.
However, despite the significant investment already made - such as the €15 million spent to bring in Argentine Lucas Ocampos from River Plate last summer - Ranieri believes that promotion was far from straightforward.
"It was easy to say, but it is much harder to do," the former Juventus trainer added.
"So I am delighted that my players have made incredible efforts. It was not easy for them. This is the first time in their lives that some of them have achieved something like this. Teams always play well against us and we had to play every game 200 per cent."
Monaco are top of Ligue 2 with 70 points, six ahead of second-placed Guingamp.