John T. Downey was born March 14, 1896, at Bridgeport, Pennsylvania.

Prior to his enlistment with the Constabulary, he served with the US Navy from July 19, 1918, to October 9, 1919. He enlisted with the Constabulary June 1, 1924, when he was 28 years old.

On August 22, 1927, at 11:30 a.m., Private Downey, accompanied by Privates Winfield S. Brown, Wallace S. Farr, and Lieutenant Thomas F. Martin, was ordered to assist Allegheny County Sheriff Robert H. Braun disperse an unruly crowd at Acmetonia, near Cheswick. The crowd had gathered to protest the execution of Nicola Sacco and Bartolomeo Vanzetti in Massachusetts. While trying to disperse the protestors at Guido Grove, Hamar Township, Private Downey was shot three times and died a few moments later.

Private Downey is buried in St. Augustine Cemetery in Upper Merion Township. He was survived by his mother, Mrs. Agnes Downey, of Bridgeport.

At 31, Private Downey had completed three years and three months of Constabulary service.