But the secret to his success is a carefully crafted rapport with his subjects. As a result, his work has forever changed the definition of what a "great sports photograph" should be.

Born to a family of sports fans in Texas in 1943, Iooss discovered photography at age 15 when his father gave him a camera. Within a year, he had begun photographing professional football games. At just 17, he got his first assignment for Sports Illustrated. By 20, he was shooting the magazine's covers.

Iooss's images have appeared on over 300 covers of Sports Illustrated—more than any other photographer in the world. In a career spanning more than 60 years, he has worked with almost every athlete at the top of their game, including Muhammad Ali, Michael Jordan, Pele, Cristiano Ronaldo, Michael Phelps, Tiger Woods, Serena Williams, Kelly Slater and Kobe Bryant.

Iooss has photographed every single one of the first 52 Super Bowls; published a book on the 18 months he spent following U.S. athletes as they prepared for the 1984 Olympics in Los Angeles called Shooting for the Gold; created a New York Times bestselling photo essay, Rare Air, with Michael Jordan; and shot campaigns for the likes of Nike, Adidas, Coca-Cola, and more.

In recent years, his pictures have been the subject of several gallery shows and a solo artist auction at Christie's New York in 2020 called Athlete: Photographs by Walter Iooss, Jr. The exhibitions include Athlete: The Sports Illustrated Photography of Walter Iooss at the Newseum in Washington, D.C. in 2009; Sport: Iooss and Leifer at the Annenberg Space for Photography in Los Angeles in 2009; and LEGENDS: The Sports Photography of Walter Iooss at the Lyman Allyn Art Museum in Connecticut in 2019-2020.

In 2018, Iooss was inducted into the International Photography Hall of Fame.