He held this post until 1903 when he was promoted to full professor, being named Perkin Professor of Mathematics in 1913 on the death of the holder of the chair William Elwood Byerly who had taught Osgood as an undergraduate and had then been his colleague for 23 years.
Siya gaganapin sa post na ito hanggang 1903 kung kailan siya ay itaas sa buong propesor, na pinangalanang Perkin Propesor ng Matematika sa 1913 sa ang kamatayan ng ang may-hawak ng chair William Elwood Byerly na nagtuturo Osgood bilang isang undergraduate at pagkatapos ay nagkaroon na ng kanyang kasamahan para sa 23 taon .