William J. "Bill" Costello was born on March 19, 1894 in the Bellevue section of West Scranton, Pennsylvania, the oldest son of renowned penman Patrick W. (P. W.) Costello and Mary Agnes Mahon. In 1916, he married Anna Jane Calpin, who was also born in Bellevue. They had four children: William J. Costello, Jr., Robert J. Costello (Brother Gordian Faber), Mary Agnes (Corbett), and John J. Costello.
When he was still a student at Central High School, Bill was taught by his father to letter and illustrate. When he was 16, some of his drawings were published in the Scranton Times as part of a six-week series, 'For Our Artists to Color.'
In 1917, at the age of 22, Bill opened a commercial sign shop ('Costello Signs') in downtown Scranton. He painted large wooden signs for local businesses and lettered show cards for window and floor display in stores and theaters. He also lettered names on office windows and cars, high school and college diplomas, and certificates and banners for local veterans’ groups. Bill lettered a large banner (30 x 46 in) listing past commanders of General J. P. S. Gobin Camp No. 41, Spanish American War Veterans. It hangs in the G. A. R. Museum in the Municipal Building in Scranton.
In 1920, the Scranton Republican published an article, titled "Costello Turns Out Quality Sign Work," which read:
High class work in the line of commercial and show card lettering is being turned out by W. J. Costello and a capable assisting staff of men at 209 Wyoming Avenue. There is an attractiveness about Costello signs that command attention. The coloring and general style of lettering put them in a class by themselves.
This concern is rushed with business. One of their latest products adorns the front of the Army and Navy Sales Company store in the 100 block of Lackawanna Avenue. The sign is thirty feet in length with the figure of a soldier at one end and the design of a sailor on the opposite side. Between the two are large, colored letters spelling out the name of the firm. Picture work is a new feature of the business. It is being developed with ever increasing demand for production carrying the Costello stamp of quality. (Scranton Republican, October 6, 1920, p. 17)
Mr. Costello's career as a commercial sign painter spanned fifty years. As his sign business grew, he moved his shop from one location to another in the center of the city, all on the second floor of commercial buildings. His first shop was located at 517 Lackawanna Ave and later, at 209 Wyoming Ave in the Odd Fellows Hall, where he and his father worked from the same studio. From 1925 until his retirement in 1966, his shop was at 316 Spruce St., near the Hotel Jermyn.
Bill Costello died in September 1973, following an illness. He was 79.