WILLIAM O. SAWYER was born in Missouri on September 12, 1852 to Jason Wingate Sawyer and his wife, the former Adeline Elizabeth Offferman. He was the third of five children, coming after Charles Augustus, and Sallie; and before Frederick O., and Emma. His mother died on December 13, 1860. Jason Sawyer remarried not long afterwards. His wife Emma bore five children, Harry H, Adeline, Frank Burrows, Frank M., and Ben Sawyer.

The Sawyer family had returned to Camden by the time the 1860 Census was enumerated. They Sawyers were living at 412 Pine Street in South Camden when the 1872 City Director was compiled.

Charles A. Sawyer was appointed to the Camden Fire Department  in June of 1873 as an extra man with Engine Company 1 to take the place of Samuel S. Buzine who had been promoted to Assistant Chief Engineer, a position similar to that of Deputy Chief of Department. Charles A. Sawyer served until April of 1876, when he was not re-appointed due to a change in politics in the leadership of the Fire Department. He was among those recalled the following year, and he remained a Camden fire fighter until April of 1882.

William O. Sawyer married Catherine "Kate" Jester in 1876. The marriage produced four children, George, Adeline, Elizabeth, and Katie. The 1878 City Directory shows the family at 611 South 7th Street. William O. Sawyer was then working for L.D. Farr as an oilcloth printer, and followed that trade until 1894. 

The Sawyers were living at 916 Walnut Street when the 1880 Census was taken. William O. Sawyer was still at 916 Walnut Street. in the spring of 1881. The 1882-1883 and 1883-1884 City Directories show the Sawyers at 810 Walnut Street. By the end of 1884 they had moved to 901 Walnut Street.

In April of 1894 William O. Sawyer was appointed to the Camden Fire Department, replacing, according to the Philadelphia Inquirer "S.W. Hyde". He began serving in May, along with new appointees Joseph Logue, William Patterson, George Cox, Samuel Curriden, John A. Dold, William Jobes, David Andrews and Albert James. 

William O. Sawyer was assigned to Engine Co No 1 at 409 Pine Street. In 1894 the personnel were as follows: Foreman John A. Stockton; Engineer, G. Rudolph Tenner; Driver, Joseph Ayres; Stoker, Wilson Bromley; Hosemen, Andrew Miller, William Jobes, and William O. Sawyer.

William O. Sawyer is listed at 901 Walnut Street in the 1906 City Directory. It appears that he bought adjoining homes at 953 and 955 South 9th Street shortly afterwards. The 1910 Census shows William O. and Kate Sawyer at 955 South 9th Street. Daughter Katie and her husband William Rogers lived with them, daughter Adaline and her husband James Hughes lived next door at 953 South 9th Street. William O. Sawyer was still serving as a member of the Camden Fire Department when the 1914 City Directory was compiled. He had by this time been promoted to the rank of Lieutenant. He and wife Kate were then living at 953 South 9th Street and were still at that address in late 1918. 

By January of 1920 William O. Sawyer had retired from the Camden Fire Department and moved to 25 East Stiles avenue in Collingswood, New Jersey. He and his wife lived with their daughter Adaline Hughes, her husband James, and their children.

William O. Sawyer passed away on December 24, 1945.