Mr. Smith played an important role both on the concert stage and behind the scenes, earning the reputation over 41 years as the orchestra's "iron man" - in his office every day, ready to conduct, ready to undertake one of a dozen projects.
He had to be prepared to conduct every concert so he could step in if another conductor were taken ill. He often played piano, organ or celesta. For many years, he also saw to it that the library supplied parts to the players that were clearly marked to reflect the interpretations of each conductor.
He also checked the information in the printed programs, from the names of movements in a symphony to dates, names and history. He was a frequent lecturer and radio commentator for orchestra broadcasts. His interest in composition was reflected in performances by the orchestra in 1954 of an overture he had written, and in transcriptions he made of Bach organ works.
Joseph H. Santarlasci, the orchestra's assistant manager through much of Mr. Smith's tenure, once called his knowledge of music "encyclopedic. He checked details of the printed program every week. He knew all the music. If Bill said the program was right, it was right."
Mr. Smith, who grew up in Haddon Heights, was a pianist and musicologist who had studied at the University of Pennsylvania. He joined the Philadelphia Orchestra in 1952 as principal keyboard player and was named assistant conductor that same year. He was made Eugene Ormandy's associate conductor in 1976.
Mr. Smith's first appearance at an orchestra subscription concert was in 1953 when composer Igor Stravinsky took ill and could conduct only part of the program. Mr. Smith led the first half - music by Glinka and Tchaikovsky - but, as he explained in a memoir written for the Curtis Institute, "Stravinsky had to conduct his own Petrouchka because I was the pianist" in the second half.
From 1956, when he succeeded assistant conductor Samuel Antek, Mr. Smith planned and led the children's concerts the orchestra gives on Saturday mornings throughout the season, and evening concerts for middle school and high school students at the Academy.
In recent years, he conducted the annual Messiah performances and the New Year's eve program, and regularly led two sets of subscription concerts each year.
The orchestra's concertmaster, Norman Carol, said Mr. Smith's death "is a great loss to us and to the city. He had had a huge impact on most of the listeners at our concerts. They first heard the orchestra in his student concerts."
Mr. Smith had offers to become music director of orchestras in smaller cities. He always declined, saying working with the Philadelphians was more important to him than being the boss of a lesser ensemble. Still, he sometimes expressed irritation that his career had not taken him further. He joked that had his name been more difficult to pronounce, he might have become conductor of another major orchestra.
He added work with other orchestras, however, and held posts as music director of the Trenton Symphony, the Amerita String Orchestra in Philadelphia and, until his death yesterday, the Allentown Symphony.
He became conductor of the orchestra at the Curtis Institute of Music in 1953 and continued to work with the student ensemble until last fall. He was also conductor at the New School of Music until it was absorbed by Temple University in 1986. When the Philadelphia Orchestra began to play summers at the Saratoga Festival, beginning in 1966, he became conductor of the Saratoga School of orchestra studies, a summer program for high school-age players.
He became artistic adviser of the Temple University Music Festival in 1975. He also had conducted for the Philadelphia Grand Opera Company. For many years, he was music director of "Music at the Museum," a series at the University Museum. He also was the commentator on the orchestra's nationally syndicated radio broadcasts.
After his marriage to flutist Deborah Carter, an orchestra student audition winner in 1968, they performed together frequently. Mr. Smith composed Flute Magic, a work for flute and electronic tape, for her in 1971. At his death, he left incomplete a Flute Sonata he was writing for their performance together.
In his subscription concerts, Mr. Smith had increasingly sought to widen the Philadelphia Orchestra's musical horizons. What was to be his next program, scheduled for April 15-17, will include the premiere of Scott Lindroth's Clash and Glitter and the revival of Robert Suderburg's Concerto for solo percussionist and orchestra - a work Mr. Smith had introduced to Philadelphia more than 10 years before. Luis Biava will conduct that program.
Because he had always been ready for any occasion, Mr. Smith's increasing absences in recent seasons seemed all the stranger. He did not accompany the orchestra on its European tour last summer, and Biava, the principal second
violin and a conductor trained in Colombia, conducted the student concerts last spring.
While conducting Pictures at an Exhibition at a children's concert at the Academy on April 27, 1985, Mr. Smith suffered cardiac arrest and toppled from the podium. Five doctors were in the audience that morning and they revived him backstage.
In addition to Carter, his wife, Mr. Smith is survived by four children
from his previous marriage to singer Ethylwyn Whitmore. They are Hilary,
Mallory, Meri and David. A memorial service will be scheduled soon, and Carter said she wants to establish a fund in Mr. Smith's name to help young performers.
Kluger said that the orchestra would play a memorial work at its concert tonight and that other memorials and tributes are being planned.