Culpo, who won the Miss USA title in June as Miss Rhode Island, is the first American contestant to take the Miss Universe title in more than a decade.
The 21-year-old beauty (click below for photos of Culpo through the years) dazzled in a tight navy blue mini with a sequined bodice, followed by a purple and blue bikini and red velvet evening gown.
She told reporters after the show, "It's such an honor to be representing the USA in an international beauty contest in spite of all the tragedy that's happened in this country lately. I really hope that this this will raise everybody's spirits a little."
Culpo stepped in as an "Extra" special correspondent during the pageant to get beauty secrets and tips from the other contestants. Watch the video to find out the beauty benefits of snail cream, lime juice and ice!
Olivia also spoke with "Extra" backstage about her diet regimen, including a high protein, low carb diet. Check it out!
Miss USA Olivia Culpo is the new Miss Universe! The Boston University sophomore bested 88 competitors for the crown.