Born to German immigrant parents, Bruno Ertz received his basic education in Manitowoc. At the age of thirteen he received a watercolor set for Christmas and thus began his love of art. He also worked in local factories and shipyards until he was fifteen, when he decided to pursue a career in art.
Ertz was a largely self-taught artist who specialized in
painting watercolor miniatures of birds, butterflies, and insects, striving for such perfect realism in his subjects that he studied them under a microscope. He sent a packet of his miniature watercolors to F. H. Crittenden at the Smithsonian Institution who replied, “I have carefully examined your work and have shown it to members of the divisional force. We all think the paintings the finest of their sort that have ever been produced in this country.”
He moved to Milwaukee around 1890, and was listed in the Milwaukee Business Directory in 1891. Bruno Ertz and Frank Bressler opened a studio in the Iron Block building from 1891 through 1892. In 1896, he moved to Detroit where he and Percy Cuthberg Nash were partners in Nash and Ertz, Portrait Artists, until 1898.
Returning to Milwaukee around 1900 he shared studio space in the University building with artists Elizabeth Brah and Lillian E. Rumpel. He returned to Manitowoc and lived there from 1918 through the 1920s.
During the Depression, Ertz moved to Milwaukee to work under the Federal Art Project at the Milwaukee Public Museum, later attaining staff status until his move to Elgin, Illinois, in 1948. His work can be found in the permanent collections of the Charles Allis Art Museum and Milwaukee Public Museum in Milwaukee, and the West Bend Art Museum. Bruno Ertz was a member of the Society of Milwaukee Artists now known as the Wisconsin Painters & Sculptors and Artists of all Media.