[3] He graduated from Columbian University,[4] then co-founded the Washington Dental College in 1897 and served as the dean and treasurer of that school.

[6] President William Howard Taft signed legislation creating the United States Navy Dental Corps on 22 August 1912.

[10] Dr. William Cogan retired from the Navy on his 70th birthday as a Lieutenant Commander,[11] and was once again appointed as the Dean of the Georgetown University School of Dentistry.

[13] On 8 June 1932, he received an honorary Doctor of Laws (LL.D) from Mount St. Mary's College for his role in establishing the Dental Corps of the United States Navy.

[12] In May 1934, then Chief of the Navy Dental Corps Harry E. Harvey presented Dr. Cogan with the keys to the Omicron Kappa Upsilon honors fraternity.

[8] However, earlier sources including articles in The Evening Star, the Register of the Commissioned and Warrant Officers of the United States Navy[11] as well as Dr. Cogan's tombstone[9] record his date of birth as the 21st of May.