In the 1900 Federal Census, Paul McCoy is found living in his father's household in Precinct 5, Pittsburgh city Ward 6, Allegheny County, Pennsylvania.
Members of the household were:
Head John C. Mccoy M 50 Canada England
Wife Catherine Mccoy F 46 Pennsylvania
Son Lawrence Mccoy M 16 Pennsylvania
Son John Mccoy M 14 Pennsylvania
Son Paul Mccoy M 11 Pennsylvania
Daughter Alice Mccoy F 9 Pennsylvania
Daughter Katie Mccoy F 7 Pennsylvania
Son Thomas Mccoy M 3 Pennsylvania

In the 1910 Federal Census, he is living in his mother's household in Pittsburgh Ward 1, Allegheny County, Pennsylvania.
Members of the household were:
SELF Catherine M Mccoy F 54y Pennsylvania
SON John F Mccoy M 23y Pennsylvania
SON Paul J Mccoy M 21y Pennsylvania
DAU Alice M Mccoy F 19y Pennsylvania
DAU Pierre K Mccoy F 16y Pennsylvania
SON Thomas Mccoy M 13y Pennsylvania

He registered for the draft on June 5, 1917. According to his registration card, he was a fireman for the city of Pittsburgh, he was married & had not previously served in the military. His physical description was medium height & build with blue eyes & black hair.

In the 1920 Federal Census, he is living in Allegheny County, Pennsylvania.
Members of the household were:
SELF Paul J Mccoy M 32y Pennsylvania
WIFE Irene M Mccoy F 27y Pennsylvania
DAU Mary L Mccoy F 2y Pennsylvania
Hattie Cowan F 30y Pennsylvania
Mamie Cowan F 24y Pennsylvania

In 1940, he is living at the Civilian Conservation Corps Camp in Camarillo, Ventura County, CA. The census record shows he is divorced, his occupation is listed as tile setter, industry is listed as Camp Overhead & his place of residence on April 1, 1935 is listed as Cleveland, Ohio.

He registered for the draft on November 28, 1942. According to his registration card, he is living at Camp Callan St, Hospital, San Diego, CA & is employed by the US Government at Camp Callan.

In the California Death Index his mother's maiden name is listed as Trainor.