“I’m an overzealous poser: One-two-three-four,” said Ms. Rocha, striking a pose a second, a skill that has earned her the title “queen of posing” from Tyra Banks. “I’m known for this, it’s my brand. You go home tonight and you write down, ‘What is my brand? Am I the sexy girl? Am I the sporty girl?’ You are a company and you’re going to brand yourself.”

On the morning that Oxygen announced the show’s celebrity lineup, Ms. Rocha was sitting on the porch of her Westchester home, which stands on a hill and overlooks a wild garden. Ms. Rocha and her husband, the muralist James Conran, recently sold their Gramercy Park condo for a reported $1.51 million; the couple has been renting in Hastings-on-Hudson since March to try on life in the suburbs. “It’s weird to have to drive every time you want to get food,” Ms. Rocha said, “but then again, we found all these cute little chains, like the Cheesecake Factory.”

Ms. Rocha was wearing snakeskin-print jeans, a black T-shirt and no shoes. She offered her visitor a soft drink: Coke, Diet Coke or Coke Zero. As part of an ongoing effort to balance her high-fashion work with more commercial spokeswoman roles, Ms. Rocha last year appeared in a Diet Coke campaign shot by Karl Lagerfeld.

“For so long we were told that we had to be quiet, hush-hush, that fashion had to be untouchable,” Ms. Rocha said. “In the beginning I thought maybe I shouldn’t do that or say that or take that job because it’s not high fashion enough. But when high fashion is done with you, guess what? You go back to your parents’ basement and no one ever hears from you again.”

Ms. Rocha grew up south of Vancouver in the shoreline city of Richmond, British Columbia. Her mother is an Air Canada flight attendant; her father works as a V.I.P. travel concierge in Toronto. Scouted at an Irish dance competition at age 14, Ms. Rocha, in a few short years, went from doing catalog shoots in Asia to working with the star-making photographer Steven Meisel, to dancing the jig down Jean Paul Gaultier’s runway in 2007. That year, American Vogue featured her on its cover as one of “The World’s Next Top Models,” announcing the “Coco Moment” and suggesting that the industry was ready for another supermodel.

But Linda, Christy and Naomi were illusive, glamorous creatures that levitated high above the masses. Ms. Rocha’s approach to her career is, in turn, more populist — a dismantling of the pyramid. On the Web is where she reveals the more prosaic moments of a model’s existence, responds to fans and airs grievances against the industry. “I’m a 21-year-old model, 6 inches taller and 10 sizes smaller than the average American woman,” Ms. Rocha wrote on Tumblr two years ago after reports surfaced that she had gained a few pounds. “Yet in another parallel universe I am considered ‘fat.’ ”