Geiberger won 11 tournaments on the PGA Tour, one of which was the 1966 PGA Championship. He won the Players Championship in 1975, and played on the American Ryder Cup teams of 1967 and 1975. Geiberger also won 10 times on the Senior PGA Tour, now called the Champions Tour.
During the second round of the Danny Thomas Memphis Classic in 1977, Geiberger became the first player in history to post a score of 59 (−13) in a PGA Tour-sanctioned event. Starting on the 10th tee of the Colonial Country Club in Cordova, Tennessee, he shot a bogey-free round of six pars, 11 birdies, and an eagle on the 6,577-metre layout. Geiberger won the tournament, though not handily.
He shot even-par 72 in the first and third rounds and was two strokes down to Gary Player on Sunday after a 38 (+2) on the front nine put him at 241 (−11) for 63 holes. He regained the lead with a 32 (−4) on the back nine to finish at 273 (−15), two strokes ahead of Player and Jerry McGee.
