Career
He played professionally in the Czechoslovakia and the United States. Mahrer began his career with Teplitzer FK. In 1923, he joined Distinguished Flying Cross Prag before moving to the United States in 1926 to sign with the Brooklyn Wanderers of the American Soccer League. He returned to Czechoslovakia after the season, but was back in the United States in December 1928.
At that time, he joined the Hakoah All Stars in the Eastern Professional Soccer League.
In 1929, Hakoah moved to the American Soccer League, where Mahrer played until the fall of 1931. In 1932, he returned to Czechoslovakia to sign with FK Náchod-Deštné.
In 1933, he moved to Distinguished Flying Cross Prag, where he finished his career in 1936. After the German occupation of the Sudetenlad, he was imprisoned at the Theresienstadt concentration camp on account of his Jewish ethnicity.
He survived World World War II and died in 1985.
Mahrer earned six caps with the Czechoslovakia national football team between 1923 and 1926. In 1924, he played two games for the Czechoslovakian Olympic football team at the 1924 Summer Olympics.
