A graduate of the University of Arizona, Corey Leff—better known as JohnWallStreet—began his career in sports talk radio at the Fox Sports Radio affiliate in Tucson. After a couple of years covering his beloved Wildcats, the New Jersey native left Southern Arizona for sunny South Florida. Leff spent much of the next decade honing his business skills at a pair of tech-based startups. In 2012, he returned to the tri-state area and entered the world of equity research. Leff spent the next half decade at a NYC-based sell-side TMT firm. In 2017, he pulled his sports, business and finance background together with the launch of JohnWallStreet. Leff left Sportico in 2023.