The Bagley House is a two-and-one-half-story French Renaissance Revival mansion built of dark brick and brown stone. Evidence has revealed that the house was designed in the French Renaissance Revival style by the Detroit firm Rogers and MacFarlane, while it was previously believed to have been designed by Shepley, Rutan, and Coolidge of the Richardson firm since the family had hired Richardson to design the Bagley Memorial Fountain. The French Renaissance Revival style house has some similar application of materials of H. H. Richardsonian Romanesque. It has a massive gable roof and a tower with conical roof. The entrance is set into a round arch and the roof dormer features a bay window. The façade contains multiple surface and window treatment, including sculptural elements by Julius Melchers around the entrance.