From 1899 to 1902 he did an apprenticeship as a carpenter and then attended the technical schools in Offenbach. Between 1903 and 1908 he worked in Joseph Maria Olbrich's studio in the Darmstadt artists' colony. Olbrich designed the Tietz department store in Düsseldorf, making Schaefer an employee of the Schöndorff company, which carried out the interiors of this house. In 1920 he moved to Rudolph Karstadt AG in Hamburg, but also built for other clients during this time.
In Germany there are still many Karstadt buildings that were made by Schaefer, e.g. at Hermannplatz in Berlin. His department store buildings are characterized by strong verticals and are influenced by department store and high-rise architecture in the US.