WALTER STILES MATTISON was born in Camden, New Jersey on March 19, 1886. He was the son of Joseph B. Mattison and his wife, the former Maggie Pennington. He was the youngest of three children, coming after Samuel K. and Rebecca L. Mattison. The Mattisons were originally from Bridgeton, New Jersey. Joseph Mattison had worked as a farm laborer there before coming to Camden in 1882. The family is listed in City Directories at 54 North 2nd Street from 1883 to 1885, Joseph B. Mattison's occupation being given as seaman. The 1887 Directory states that he was working as a driver for the Camden Horse Railroad Company, but gives no address.

It is unclear as to what became of Joseph B. Mattison. He does not appear in Camden City Directories after 1889. Maggie Mattison is listed by herself from 1891 through 1894 at 105 South 5th Street. The 1895 City Directory shows Maggie Mattison at 701 Berkley Street. The 1896 and 1898 Directories shows Margaret Mattison, widow of Joseph, at 703 Berkley Street. The 1900 Census also states that Joseph B. Mattison had passed away. The family was living at 704 Berkley Street. Mrs. Mattison did have a boarder, John T. Davis Jr., a house painter.  City Directories and census records indicate that John T. Davis began boarding with Maggie Mattison around 1894 and that he was still boarding with her as late as 1911. It is likely that he and Mrs. Mattison had a relationship and that Mr. Davis was something of a stepfather to Walter Mattison.

City Directories show Maggie Mattison, Walter Mattison and John Davis at 701 Berkley Street from 1901 to 1904, and at 422 South 7th Street in 1905 and 1906, 728 New Street in 1907, and at 563 Mickle Street in 1908 through 1910. The 1910 Census shows of the three children, only Walter was still living with their mother. Walter Mattison was at that time employed as a grocery salesman.

On June 7, 1911 Walter S. Mattison married Loice Winford Corson at the First Methodist Episcopal Church at South 6th Street and Stevens Street. The witnesses were Dorothea Corson and Charles H. Suders. The marriage produced two children, Daughter Leah Mae in 1915 and so Walter S. Mattison Jr. in 1916. 

The young couple were making their home at 576 Auburn Street by 1913. By the end of that year the Mattisons had moved to 575 Clinton Street, which would remain the family home through at least 1947. 

On April 11, 1917 Walter S. Mattison was appointed to the Camden Police Department, along with Nathan Petit. Both served well over 30 years with the department. At least one other man, Harry Kyler, was appointed the next day. He too put in over 30 years with the Camden Police.

On September 12, 1918 Walter S. Mattison registered for the draft. After the war Walter Mattison began rising through the ranks in the police department. City Directories from 1923 through 1926 show him as the turnkey at the City Hall Annex, which is to say, he managed the jail. In 1929 Walter Mattison was promoted to Sergeant, and was assigned to the Second District house on Chestnut Street.

In 1934 Walter Mattison's daughter Leah Mae Mattison married George Getley, an officer of the Camden Police Department assigned to motorcycle duty. The marriage produced two grandchildren, Janet L. Getley and George E. Getley Jr. by 1940. Sadly, Walter Mattison's wife passed away in 1941 and George and Leah Mattison Getley's marriage foundered shortly before the compilation of the 1943 City Directory. By 1946 Leah had moved back to 575 Clinton Street. Leah Mattison Getley remarried after 1946, moved to Pennsauken by 1954, and later moved to Texas. 

Walter S. Mattison was promoted to the rank of Lieutenant in 1943, and to Captain in November of 1949. Captain Mattison died of pneumonia on August 1, 1950 after short illness. He had been living at 541 Washington Street, the home of Camden County freeholder Oscar Moore, to whom he was related to nay marriage, Mrs. Moore having been a niece of the late Mrs. Mattison..