After playing for Universal Montevideo Alfredo Ghierra was one of the founding members of Defensor Sporting, a club whose name he chose, which was inspired by the Defensores de la Huelga, a team of workers from a glass factory in Punta Carretas. Ghierra was with Defensor for its early years and helped them obtain promotion to the top-flight in 1914. After relegation in 1917, Defensor gave up membership in the League and Ghierra moved on to Universal Montevideo, with whom he won a Copa de Honor in 1920.
In 1922 Defensor was re-founded and Ghierra returned to play with the team he had helped found, remaining there until the end of the decade, except for 1925, as after the championships he joined Nacional Montevideo on its European tour. He also made his début with the national team, taking part in the 1924 Paris Olympics, winning the gold medal, and in the 1923-24 and 1926 Copa America, winning all three competitions. Ghierra earned a total of 14 caps.