Though born in Havana, Ramón Fonst spent much of his youth in France, where he received a fencing education. As a 16-year-old youth, he upset the French épée fencers at the 1900 Paris Olympics, winning the amateur event. He also fought in the competition that faced the best amateurs against the best masters, in which he ranked second behind Albert Ayat. These were the first Cuban and first Latin American medals in Olympic history. He added to his collection at the 1904 Games in St. Louis, winning both the foil and épée events and joining American Albertson Van Zo Post and fellow Cuban Manuel Díaz to win the foil team competition.
For 20 years, Fonst disappeared from the Olympic stage, but he did not stop competing, fencing in events over the world. When the first formal Cuban team entered the Olympics in 1924, Fonst was again an Olympian, albeit without a medal. His career was still far from over, as Fonst dominated the fencing competitions at the 1926 and 1930 Central American and Caribbean Games, winning five golds. In 1938, at the age of 55, he returned to these Games and won a sixth gold - his last major victory. As a pun on his matronymic which was Segundo, Fonst’s nickname was El nunca Segundo, roughly meaning “He who never comes in second”. Fonst continued to be involved in sports, serving as the president of the Cuban NOC (1941-46) and as a government advisor on physical education.