JOHN M. GRAY was born in Pennsylvania in 1820. He was living in Philadelphia as late as the 1860 Census. When the Census was taken in June of 1870, the Gray family was living in Camden's North Ward. He was living with his wife Sarah and his children Sarah, 27, Peter, 23, and John S. Gray. The family lived on the same block as Albert Doughty, John Anderson, and Isaac Anderson who all would later serve is the Camden Fire Department.

John M. Gray was a harness maker by trade. He was living at 30 North 5th Street when he was appointed to the Camden Fire Department on February 8, 1872, taking the place of Charles Elfreth, who had been promoted to Driver. Although he was 52 at the time, and that his son John would be appointed to the department a few years later, Fire Department records concerning his occupation and the occupation listed in the 1870 Census indicate that it was John M. Gray, the father, who was appointed to the Fire Department in 1872.

John M. Gray served as an extra man with the Hook and Ladder Company, known in more recent times as Ladder Company 1. John M. Gray resigned from the Fire Department on October 8, 1872. 

In March of 1878 John M. Gray was appointed janitor of Camden's City Hall. When the Census was again taken in 1880 he was still working as the janitor at Camden's City Hall. He lived on premises with his wife Sarah. Suffering for some time with asthma, he died in mid-September of 1880,

John M. Gray's sons John Gray and Peter S. Gray both went on to serve with the Camden Fire Department. They came into the department separately in 1874 and served for many years, thereafter.