Kelly Bensimon

As a model, she appeared in magazines such as Elle, Cosmopolitan, and Harper's Bazaar, and she was once the face of Clarins. She appeared on the cover and in a six-page pictorial in the March 2010 edition of Playboy, which was photographed by her ex-husband Gilles Bensimon. In September 2011, Killoren Bensimon was on the cover of Shape and was featured in a pictorial based on her exercise routine.

She has worked as a host of various events including IMG fashion week, and of the IMG swim shows in Miami. She was a spokesperson in 2006 for Wool as part of their Test Marketing Productions (TMP);. Bensimon hosted and modeled in menswear events with GQ magazine. She was also an "ambassador" for Spring 2007 Mercedes-Benz Fashion Week in New York City.

Killoren Bensimon has had several jewelry collections. Her first line of jewelry was sold exclusively at Barneys New York. Her second line of jewelry was sold at Bloomingdale's in fall 2007. On June 24, 2010, Killoren Bensimon announced the launch of her fourth jewelry collection, Kelly by Kelly Killoren Bensimon. The collection included mixed metals, leather, feathers and crystals and was sold at Intermix stores across the U.S. to support Feeding America. For spring 2011, Bensimon's jewelry collection was sold at Wink, W Hotels, and Dash. She also sold a jewelry collection on HSN. In 2013, she launched a fragrance, In the Spirit of, and a candle line called Baiser Rose. In 2019, she launched an outerwear line called Enville by Pologeorgis.

Her television career most notably includes Bravo's The Real Housewives of New York City (seasons 2-4), which she joined in 2009 as a full cast member. She stirred controversy while on a cast trip to the island of Saint John, U.S. Virgin Islands. Killoren Bensimon appeared on Bravo's Odd Mom Out in episodes 9 and 10 of season 2. She also appeared on WEtv's reality series Million Dollar Matchmaker. Killoren Bensimon starred in the fourth season of The Real Housewives Ultimate Girls Trip, a spin-off featuring various women from The Real Housewives franchise, which premiered in December 2023 on Peacock.

Killoren Bensimon has also worked as a writer, producing three books for Assouline Publishing: In the Spirit of the Hamptons (2 volumes), American Style, and The Bikini Book. A portion of the author's proceeds were donated to the Costume Institute of the Metropolitan Museum of Art. Her fourth book, I Can Make You Hot, was published by St. Martin's Press in April 2012. A portion of the author's proceeds were donated to Generositywater.org. In June 2016, Simon & Schuster published Bensimon's novel, A Dangerous Age. In August 2017, Killoren launched the sequel The Second Course, an odyssey about the food world. She is a style columnist for the newspaper AM New York. She is the editor at large for Hamptons Magazine, a free weekly with circulation of 40,000 to 50,000 and Gotham Magazine. Both publications are owned by Niche Media. She became the founding editor of Elle Accessories, but left after two issues.

After obtaining her real estate agent's license, Killoren joined Dolly Lenz Realty in New York in 2018. She has also made numerous appearances on Million Dollar Listing New York.