The 29-year-old singer walked the runway in an oversized coat with fur detail and chunky platform boots wearing heavily-lined eye makeup and a modified 1920s hairstyle.
"I've adored @marcjacobs since I was very young, so I was honored to be one of his beautiful creatures tonight," Lady Gaga wrote on Instagram.
Reality star and model Kendall Jenner also walked the runway, sporting a bouclé ensemble with feather detail. Girls actress Zosia Mamet, Mad Men actress Kiernan Shipka and K-pop star CL were among the celebrities in the audience.
Women's Wear Daily reported Lady Gaga "insisted on being treated like all the other models." New York Fashion Week came to a close Thursday after a week of new trends, including monochrome looks and different prints.
"I have a real respect for fashion designers, and it is the reason I don't have my own line and I probably never will," the star told reporters after the Brandon Maxwell show Wednesday. "If I ever do anything in fashion it's always going to be as a muse or aesthetic creative."
Lady Gaga last released Cheek to Cheek with Tony Bennett in 2014, and is working on new music with Elton John. The singer performed a musical tribute to late star David Bowie at the 2016 Grammy Awards on Monday.