O'Connor held the NWA World Heavyweight Championship from 1959 to 1961. He first won the title on 9 January 1959 from Dick Hutton, who had held the title for thirteen months. O'Connor's reign was recognized by both the National Wrestling Alliance and the National Wrestling Association. The title change was part of the rivalry between bookers Sam Muchnick and Fred Kohler, the latter of whom did not want to waste any money announcing O'Connor as the new champion. Kohler also wanted O'Connor to pay him $10,000 to wrestle at shows in Chicago, while being paid less than champions usually earned. O'Connor was so angry at the suggestion that he walked out of their meeting and later told Muchnick not to book him for any events in Chicago. The men later worked out a deal of sorts, and beginning on 19 February 1960, O'Connor wrestled in Chicago against Bruno Sammartino and Johnny Valentine, among others.