Guerra was on the eighth season of Project Runway, aired in 2010. After placing in the top, but not winning, on a number of challenges, then placing in the bottom but not being eliminated in the seventh episode, he won the challenges on the eighth, ninth and tenth episodes. He also won $20,000 for the ninth challenge, which involved both a "couture" look and a "ready-to-wear" look. During the tenth challenge, after a question from Nina García and without having expected to do so, he revealed to the judges that his pattern of bright, bold plus signs on a pant was inspired by his HIV+ status, and that he had been keeping his HIV status a secret for ten years; in an interview he mentioned that the schedule was particularly difficult for his medication adherence, despite coming shortly after a very low CD4 count. He had not previously disclosed his HIV status to his family and the show's producers and Tim Gunn spoke with him about how he wanted to handle the issue; Guerra has described feeling a sense of relief and self-love at going public with his status. He finally disclosed to his family shortly before the tenth challenge was broadcast. With a collection themed on the Day of the Dead fan favorite Guerra came in second place in the final competition held at Mercedes-Benz Fashion Week at the Lincoln Center for the Performing Arts in New York City. Oregonian Gretchen Jones took first place, and Hawaian Andy South — now Ari South — came in third. Project Runway executive producer Heidi Klum — who had pushed for Guerra to win over Jones in a lengthy split debate over the winner — appeared in a modified version of one of Guerra's final collection gowns for the Los Angeles premiere of the movie Black Swan a few weeks after the airing of the final episode. Guerra was the winner of the 2012 series first season of Project Runway All Stars, beating out season 1 designer Austin Scarlett and close friend from season 8 Michael Costello. In 2019, Guerra appeared in the seventh season of Project Runway All Stars, where he assisted Irina Shabayeva for the final challenge. Guerra also was a judge for Project Runway Season 10, episode 9, in which contestants had to make their own print for fabric and design an outfit using the fabric. The episode flashed back to Guerra's win for this challenge during Season 8.
Other notable work
On November 30, 2010, Guerra appeared with Liza Minnelli, Kenneth Cole and Cheyenne Jackson on the trading floor of the New York Stock Exchange to ring the opening bell on behalf of amFAR, to usher in World AIDS Day. Also in commemoration of World AIDS Day, he designed a limited edition of T-shirts, one with a Day of the Deadsugar skull and one with a tree of life. These shirts were sold on Piperlime.com starting at midnight on December 1, 2010. For each shirt sold, $20 was donated to amfAR. In his statement to Fox News Latino for his motivations in doing this, he said, "The Day of the Dead is celebration of our loved ones who have passed. When I was thinking of World Aids day I wanted to create something very true to who I am, and what I know. Who I've known and miss and those people in my life that still fight this disease. It's about love and continuation." In the season 10 finale episode of the hit reality competition show RuPaul’s Drag Race, contestant Blair St Clair appeared wearing a gown designed by Guerra himself. It was rewarded the “Top Toot of the Week” by the show’s official fashion review online series, Fashion Photo Ruview.
