William Jacob Hiss was born in Baltimore, Maryland on 22 June 1870. He was the son of Baltimore-born William J. Hiss, a partner in a firm of furniture manufacturers, and Annie Ames, a native of Massachusetts. He had at least seven siblings.

Hiss, a qualified electrical engineer, was later the general manager of the western division of the New York Telephone Company. He married in East Orange, New Jersey on 8 October 1898 to Eleanor Ludlow, a native of New York. A son named James was born in 1901, followed by their daughter Eleanor in 1910. The family lived in Manhattan, later Brooklyn and by 1912 in Buffalo at 189 North Street. 

In April 1912 Hiss and his wife were going on a vacation to Italy and Austria and boarded the Carpathia as first cabin passengers; their children did not accompany them.

After the survivors were landed at New York, Mr and Mrs Hiss continued on their journey aboard the Carpathia to the Mediterranean.

During WWI Hiss was an active Red Cross worker; he spent his last days living in East Orange, New Jersey where he passed away on 3 May 1941. He is buried Baltimore’s Green Mount Cemetery.