Nel-Peters 22, beat out first runner-up, Miss Colombia - Laura González and second runner-up, Miss Jamaica - Davina Bennett for the crown on Sunday night in Las Vegas, United States of America.
Demi-Leigh has a degree in Business Management and is passionate about a program she developed to train women self-defence, which she plans to expand and help as many women as she can, the Miss Universe website stated.
The beauty from South Africa has earned a yearlong salary, a luxury apartment in New York City for the duration of her reign and more prizes.
Last year's victor was Iris Mittenaere, of France.
"You feel so empowered because you are on a stage with 91 other women that are strong, that are independent, that have worked really hard", she said.
Debut contestants at the 2017 pageant all hail from the Asia-Pacific region, with Nepal also making its introduction with the other two Southeast Asian nations in the annual competition.
Miss South Africa Demi Leigh Nel-Peters along with other contestants Reuters
Demi-Leigh Nel-Peters has been crowned Miss Universe.
Hailing from Sedgefield in the Western Cape, Nel-Peters dedicated her win to South Africa.
Steve Harvey returned as the show's host despite botching the 2015 Miss Universe crowning.
The Kingdom's historic debut comes thanks to 19-year-old Phnom Penh local Sotheary, who had gained extensive support and attention from local fans after winning the Miss Cambodia pageant in 2016.
Wurtzbach was one of the judges for the telecast. This took her through to the Top 3.
When Graham asked Peters how she felt about her reception, the 26-year-old model said: "I was a little nervous".