Despite his relative inexperience, Cooney's exciting wins and size, aided by expert promotion, gained him a lucrative bout with world heavyweight champion Larry Holmes in 1982. Cooney performed credibly before his corner retired him in round 13, and was regarded as having made a brave and determined effort. The view of him as tactically naive in defense was reinforced when former light heavyweight champion Michael Spinks stopped Cooney in five rounds in 1987. In his final bout, Cooney demonstrated his exceptionally hard punching power by staggering the powerful George Foreman, but was unable to capitalize on it. Cooney went on to suffer a devastating second-round knockout that ended his career.

This March 1982 issue of Sport Magazine was signed in blue by Cooney and includes a Great Moments COA.