He accepted immediately and served as assistant professor at the University of Chicago from 1900 to 1907, then associate professor to 1910 when he was promoted to full professor.
Tinanggap niya agad-agad at nagsilbi bilang assistant professor sa University of Chicago 1900-1907, at pagkatapos ay iugnay propesor sa 1910 kapag siya ay itaas sa buong propesor.