Kirchmayer was born in Oberammergau, Bavaria. After learning sculpture in Germany, he emigrated in 1880 to Boston and took up work mainly in church sculpture. He was a founding member of the Boston Society of Arts and Crafts with his work featured in an 1887 exhibition. After 1898, in the employ of Boston furnituremaking and architectural woodworking firm Irving & Casson, he worked on the buildings of the noted American Gothic-revivalist Ralph Adams Cram.
Kirchmayer's notable work around Boston includes carvings in The Church of the Advent, Brimmer Street, Boston; All Saints' Church, Ashmont, Dorchester; the Second Church, Newton; and Unity Church in North Easton. He also designed the mantling of the Anderson Memorial Bridge over the Charles River. His work outside the Boston area includes carvings in the Church of Saint Mary the Virgin, West 46th Street, New York City; St. Mary's Anglican Church, Windsor, Ontario; the Church of the Saviour, Syracuse, New York; and the James J. Hill House, St. Paul, Minnesota. At $1.00 an hour, he was the highest paid workman on the Hill House construction project.