A much-improved Austria begin their campaign against tournament favourites France in Duesseldorf on Monday and will also play Poland and the Netherlands in Group D, arguably the toughest section in the tournament.
Rangnick, who hails from near Stuttgart in south-west Germany, is coming into his first major international tournament as a coach at the age of 65.
"This ranks very high for me because we have prepared for over two years for this day tomorrow," Rangnick told reporters.
He was appointed by Austria in 2022, arriving after an unremarkable spell at Manchester United.
Rangnick then opted to remain in charge of Austria when he turned down an approach from Bayern Munich last month.
"It was a very long qualifying campaign and we were then drawn in the strongest group, but tomorrow it is finally starting for us and we are really excited.
"There is joy above everything else but we also have ambition to qualify for the knockout stage."
Austria finished second in their qualifying group behind Belgium and had recorded six consecutive wins before a 1-1 draw with Switzerland in their last friendly game prior to the Euros.
Those wins included a 2-0 triumph over Germany last November and a 6-1 trouncing of Turkey in March.
Now they face the top-ranked European team, who beat them 2-0 when the sides last met in the UEFA Nations League in Paris in September 2022.
"We are playing against maybe the big favourites, the World Cup runners-up and definitely the nation with the best squad and best forwards," Rangnick said.
"We know we need to perform to our best level. It is crucial that we are courageous and convinced of our own strength."
Meanwhile Bayern midfielder Konrad Laimer admitted it would require an "extraordinary" performance to beat France as he dismissed suggestions they could be distracted by non-footballing issues.
French team press conferences in recent days have focused on upcoming elections in the country, in which the far-right National Rally could become the biggest party.
"France has such a great squad with so many individual talents," Laimer said.
"But this is about playing our own football. When you play against teams like France you have to take their superstars out of the game.
"You need an extraordinary performance to do that but we know we are able to and we have been preparing for a long time for this.
"This is a Euros in our neighbouring country, a country where so many of our players play and have been living for a long time."
