Born in Baltimore and raised in Walbrook and in Elkridge, he was a 1954 Howard County High School graduate.
"His career in film began in high school," said his brother, John E. Hewitt of Glen Burnie. "He was the one who could run the 16-mm Bell and Howell projector. As a 12-year-old, he rented films for the family."
He said his brother spent his Saturdays at the old Folkemer film supply firm and got his start at the Elkridge drive-in on Washington Boulevard. An usher, he built phonograph turntables and played music before the feature began at nightfall and later operated the projector.
In 1955, he began working at the Hollywood Theater in Arbutus. From 1956 to 1961, he managed the old Edgewood Theater on Edmondson Avenue near the home of Gov. William Donald Schaefer, who was a friend and displayed his early City Council campaign materials at the movie theater.
Mr. Hewitt, who personally preferred foreign and classic American films, founded the Baltimore Film Society. On Monday nights he secured permission from the Durkee chain that owned the Edgewood to have the club's screenings there.
"He built up a membership and the place was packed," said his brother.
In 1961, he leased the Rex on York Road near Cold Spring Lane for his cinema club, which he ran with a partner, Ronald L. Freeman. When he found there was not sufficient patronage to meet expenses, he began showing movies that tested Maryland's standards of decency. He and his partner retained lawyers and took their case to the Supreme Court. Justice William J. Brennan wrote an opinion, but Maryland's right of censorship remained.
Mr. Hewitt also managed the Irvington, Avalon, Lord Baltimore and Church Lane theaters and was a Carlin's Drive-In projectionist. He also became head film technician on the staff of the downtown Enoch Pratt Free Library.
"He had a dry sense of humor and was stoic," said Marc Sober, Pratt's media research specialist. "He was not a talker unless you got him started on the state of movies today. I'd often go up in his booth at the Senator and we'd talk for hours. He knew his stuff."
He tried to open a film repertory house at the Arcade in Hamilton in 1981. He worked alongside his bother, but the project failed.
In 1984, he became the projectionist at the Senator Theatre in Govans where he remained until June.
"He was the man behind the Senator's curtain," said a fellow projectionist, Mark Kotishion. "Bill was a stickler for perfection. If the film had been made in CinemaScope, it had to be shown perfectly in CinemaScope. When the Senator got all the big premieres, Bill was the man in the booth making sure it all went off."
Thomas Kiefaber, the former owner of the Senator, said, "I don't think there was ever a better manager of the theater. If there was one light bulb out on the marquee, Bill saw it. It was like he had projector gear oil running in his veins."
Mr. Hewitt also liked silent films and spent a few days each September at the Cinesation festival in Massillon, Ohio. He also maintained a private film archive, including Technicolor prints.
"As a lender, he was very generous and wanted to share his prints," said Jeff Joseph of Sabu Cat Productions in Los Angeles. "At times his copies were shown at the Egyptian and Motion Picture Academy theaters."
A memorial will be held at 6 p.m. Dec. 2 at the Singleton Funeral Home, 1 Second Ave. in Glen Burnie.
In addition to his brother, survivors include a niece and nephew.