Cottrill was a nationally known politician, a leader of Toledo's African-American community, and a realtor in the early 1900's.  He attended Toledo High School and graduated in 1881, as president of his class.  At his death at age 60, he was the only African-American 33rd degree Mason in Toledo.

​

He was employed as a clerk for the IRS, then clerk for the Lucas County Treasurer, then clerk for the Lucas County Recorder (18 years).  He served as president of the Toledo branch of the N.A.A.C.P. and as an officer of many fraternal organizations. President William Howard Taft appointed him as the Collector of Revenue in Honolulu (1911-1915).  He opened a real estate office (1916-1924) in the prestigious Nicholas Building.