Born in Germany in 1868, Imhoff immigrated to the United States with his family and settled in Reading, Pennsylvania, where he established a successful art and fresco business. He left Reading in 1914 and made his home and studio in the St. Walburg, Saskatchewan area. From there he decorated churches in many rural villages of Saskatchewan and North Dakota as well as returning to Reading for commissioned work.
In 1891, he married Matilde Johner, the daughter of Joseph Johner. Imhoff, Matilde, and six of his seven children moved to what is now St. Walburg, Saskatchewan in 1914. Once in Saskatchewan, Imhoff started painting many of the small churches which dot the prairie landscape near his home, often for free or for very little pay. In 1926, Imhoff completed what some people consider his masterpiece: the cathedral in Reading, Pennsylvania. Many of the 226 life-sized paintings were started in his studio in Saskatchewan and then transported to Reading where they were then completed by him and his family. In 1937 he was awarded a Knighthood in the Pontifical Order of St. Gregory the Great by Pope Pius XI. He died in 1939 and is buried in the St. Walburg Roman Catholic Cemetery next to his wife Matilda. A life size equestrian statue honouring Imhoff by St. Walburg artist Susan Velder is located in the village. The Imhoff Gallery which includes his studio, home and farm is now a heritage site.