Upton appeared Friday on "Good Morning America" and said she feels good about making her story public.
"As soon as I did my article with Time, I felt a sense of relief," she said. "It's a new climate... women are coming together and you're able to have that platform to share your story and create real change for other women."
In a story published by Time
on Wednesday, the 25-year-old model claims that Marciano verbally harassed and inappropriately touched her starting when she was 18 years old.
Marciano denied the accusations in a statement to Time, which CNN obtained, calling them "absolutely false."
"I have never been alone with Kate Upton," Marciano said in the statement. "I have never touched her inappropriately. Nor would I ever refer to a Guess model in such a derogatory manner."
CNN reached out to Marciano again on Friday to comment on Upton's GMA remarks.
Upton alleges that at a 2010 photo shoot for her first Guess campaign, Marciano "forcibly" grabbed her breasts, saying he wanted to make "sure they're real."
She told GMA's Robin Roberts on Friday that she found the courage to come forward after doing a workout with some of the newer models participating in New York Fashion Week.
"A lot of girls were sharing how excited they were about the different opportunities they got and the start of their career," Upton said. "I remember being in that place whenever I got the meeting to go meet with Paul Marciano and how different my view of the industry after that meeting was and I wanted to prevent that from happening to these other girls who were just starting out."
The alleged incident with Marciano changed her perception of the modeling world, Upton said, and caused her to question herself.
As for the fashion mogul denying her allegations, Upton said she expected that.
"Honestly, I don't really need his validation for what happened," she said. "I'm not looking for him to come forward and tell the truth and honestly I expected him to do that. I think it speaks to how he's treated these allegations in the past and it used to work before but that's not the case anymore and we're being heard and our stories are taken seriously."