In 1973, Brisco made his debut for World Championship Wrestling (WCW), where he immediately made an impact. Brisco's first WCW World Heavyweight Championship win was scheduled to be over Dory Funk, Jr., capping off a multi-year feud. However, Dory claimed to be injured and missed the scheduled date. Dory later lost the title to Harley Race. Brisco won the title from Race after a brief reign, in Houston, Texas on July 20, 1973. He defended the championship against top names like Johnny Valentine, Stan Stasiak, Abdullah the Butcher, Gene Kiniski, The Sheik and Bobby Shane until losing to Giant Baba on December 4, 1974. He regained it four days later. Brisco then defended the title until losing it to Terry Funk on December 10, 1975. His loss continued the extensive feud between the Briscos (Jack and his brother Gerry) and Funks, which went on for several more years.
Brisco teamed with his brother to win the WCW World Tag Team Championship three times. As heels, they beat Ricky Steamboat and Jay Youngblood for the belts on June 18, 1983. This set up a rivalry in which the belts switched hands several times. Steamboat and Youngblood regained the belts on October 3, but the Briscos won them back on October 21. They held the title for a little over a month before dropping it back to Steamboat and Youngblood. The Briscos again won the belts the following year, from Wahoo McDaniel and Mark Youngblood.
On December 28, 1984, the Briscos challenged The North-South Connection (Adrian Adonis and Dick Murdoch) for the WWF Tag Team Championship in Madison Square Garden. The match ended in a double countout, and was Jack Brisco's last high-profile bout.
Brisco and his brother, Gerald were inducted into the WWE Hall of Fame Class of 2008.
On February 1, 2010, Brisco passed away.