Óscar Pezoa took up cycling in the 1940s after trying a variety of other sports, including soccer and basketball. Inspired by the 1948 London Olympics, he set his sights on qualifying for the 1952 Helsinki Games and displayed talent so quickly that he was chosen to represent Argentina at the 1951 Pan American Games. There, he won a gold medal in the team road race (with non-Olympians Oscar Muleiro and Humberto Varisco) and was second individually in that event. This assured his selection for Helsinki, where he was entered into the team pursuit, 4,000 metres. At the Olympics, alongside Pedro Salas, Óscar Giacché, and Rodolfo Caccavo, he was eliminated in the qualifying round by 0.2 seconds behind Switzerland. He retired shortly after winning the national road race title in 1953 and never turned professional.