[2][6] He progressed to become a mechanic, working for the Norristown Iron Company.

In 1854, he moved to the Cambria Iron Company, where he designed the first three-high rolling mill, a notable achievement.

[1][2][4] While there he was responsible for installing a Bessemer Converter and various developments in the company, staying until 1892, when he was 70.

[4] Fritz was president of the American Society of Mechanical Engineers, president of the American Institute of Mining Engineers, honorary vice president for life of the Iron and Steel Institute of London, member of the American Society of Civil Engineers, honorary member of the American Iron and Steel Institute, and recipient of the Bessemer Gold Medal, the Elliott Cresson Gold Medal, and the John Fritz Gold Medal of the United Engineering Societies.

[7] Fritz died at his home in Bethlehem on February 13, 1913, at age 90 [8]