Fernando Madeira took up swimming at the age of nine and was already setting records at the age of 15, a trend that continued as he got older. Local regulations prevented him from competing internationally in longer swims until the age of 16, so he mastered a wide range of distances, up to 1500 metres, during his career. He was selected to represent Portugal at the 1952 Helsinki Olympics, where he was joint-36th in the 400 metres freestyle and joint-48th in the 100 metres freestyle, and also played on the water polo team, which was eliminated in the qualifying round. He continued setting records into his mid-20s and did not retire from active competition until he was 30.