In 1998 in New York, when he was 31-years old, Asness, David Kabiller, John Liew, and Robert Krail, co-founded AQR Capital Management—a "quantitative hedge fund firm".
Asness was featured in Scott Patterson's 2010 publication, The Quants, along with Aaron Brown from AQR Capital Management, Ken Griffin from Chicago's Citadel LLC, James Simons from Renaissance Technologies, and Boaz Weinstein from Deutsche Bank. a "scourge of bad practices in the money management industry" with the "intellectual chops to back up his attacks". Patterson said that Asness was known as "one of the smartest investors in the world." He had been a "standout student at the University of Chicago's prestigious economics department in the early 1990s, then a star at Goldman Sachs in the mid-1990s before branching out on his own in 1998 to launch AQR with $1 billion and change, a near record at the time."