[5] Mittenaere initially only entered Miss Flandre after being contacted on Facebook by the contest organizers, due to there being a lack of candidates that applied.

[11] During her reign as Miss France 2016, Mittenaere traveled to China, Italy, Morocco, Germany, the Caribbean, and Ivory Coast.

[30] She traveled to Bali to shoot a commercial for C 1000, a vitamin brand available in Indonesia and attended Farouk Systems's Global Conference in Cancun.

[36] In June 2017, she attended Joyrich x Snoop Dogg's Fashion show at MADE LA 2017 in Los Angeles and was invited to the AmfAR generationCURE Solstice 2017 in New York City.

[42] During her reign as Miss Universe, Mittenaere traveled to the Philippines, Indonesia, Haiti, the Cayman Islands, Ecuador, Mexico, Peru, India, and Egypt, in addition to numerous trips around the United States and France.

For her last walk as the reigning Miss Universe, Mittenaere wore a Michael Cinco scarlet red ombré Couture gown, in full Swarovski crystals, which featured a fitted bodice and flowing train,[43] before passing on the crown to her successor Demi-Leigh Nel-Peters of South Africa as Miss Universe 2017 on 26 November 2017 at Planet Hollywood Las Vegas in Las Vegas, Nevada.

[44][45][46] From 4 to 9 December 2017, she participated in the Miss Universe's Christmas Tour in the Philippines, alongside her successor Demi-Leigh Nel-Peters and predecessor Pia Wurtzbach,[47] then served as co-president of the jury with Jean-Paul Gaultier at Miss France 2018, appearing on stage with the five finalists as a part of the fashion swimsuit portion of the competition and putting an end to her international pageant career.

[49] The camera crew followed Mittenaere's reign as Miss Universe, her humanitarian travel, her trips and homecoming in France, and her family's reaction to her new life.

[51] In February 2018, Iris Mittenaere presented an award at the 2018 Victoires de la Musique, wearing designer Stéphane Rolland.

[54] In March 2018, she was invited by the First Lady of Ivory Coast to attend the 7th Gala dinner of the Children of Africa Foundation, marking its 20th anniversary and the opening of a new hospital.

[55] She also participated to a Smile Train event, visiting families of cleft patients in Abidjan, Ivory Coast.

[60] The book chronicles Mittenaere's origins in Northern France and her pageantry experience, in addition to beauty tutorials and advice for young women in order to build self-confidence.

Other cities include Paris, Lyon, Toulouse, Bordeaux, Cannes, Dunkirk, Reims, Nantes in France, Brussels in Belgium and Geneva in Switzerland.

[68][69] She also attended de Grisogono Host Gala Dinner, wearing a bejewelled blue one-shoulder gown, designed by Lebanese Ziad Nakad, which was adorned in gems and sequins.

[71] In June 2022, Mittenaere was guest judge on the first episode of Drag Race France with the French fashion designer Jean Paul Gaultier.

[72] In August 2022, Mittenaere announced her engagement to French-Moroccan businessman Diego El Glaoui, with whom she had been in a relationship for three years.