De Vicenzo won his first Argentine tournament, the Abierto del Litoral, in 1942; his first World Cup in 1953; and a Major tournament, The Open Championship, in 1967. De Vicenzo is best remembered for his misfortune in the 1968 Masters Tournament. On the par-four 17th hole, De Vicenzo made a birdie, but playing partner Tommy Aaron inadvertently entered a 4 instead of 3 on the scorecard. He did not check the scorecard for the error before signing it, and according to the Rules of Golf, the higher score had to stand and be counted. If not for this mistake, De Vicenzo would have tied for first place with Bob Goalby, and the two would have met in an 18-hole playoff the next day. His quote afterwards became legendary for its poignancy: ‘What a stupid I am!’
In 1970, he was voted the Bob Jones Award, the highest honor given by the United States Golf Association in recognition of distinguished sportsmanship in golf.
De Vicenzo subsequently found great success in the early days of the Senior PGA Tour, winning the Liberty Mutual Legends of Golf two times and the inaugural U.S. Senior Open in 1980. He also won the 1974 PGA Seniors’ Championship, and represented Argentina 17 times in the Canada Cup/World Cup (leading Argentina to victory in 1953).
De Vicenzo was inducted into the World Golf Hall of Fame in 1989, and officially retired on 12 November 2006, at age 83 with over 200 international victories. The Museum of Golf in Argentina in Berazategui was founded because of his hard work. It was named in his honour upon its completion in 2006.