Von Schmidt was born in Frickenhofen, Gschwend, Württemberg, Germany. After studying at the technical high school in Stuttgart under Breymann and Mauch, he became, in 1845, one of the guild workers employed in building Cologne Cathedral, on which he worked for fifteen years. Most of the working drawings for the towers were made by Schmidt and Vincenz Statz. In 1848 he attained the rank of master-workman and in 1856 passed the state examination as architect. After becoming a Catholic in 1858, he went to Milan as professor of architecture and began the restoration of the cathedral of Sant'Ambrogio. On account of the confusion caused by the war of 1859 he went to Vienna, where he was a professor at the academy and cathedral architect from 1862; in 1865 he received the title of chief architect, and in 1888 was ennobled by the emperor.