When he was 13, his parents split up. His mother joined a firm that made theater costumes. His father gave him guitar lessons, and young Bill played 50-cent gigs with musicians who would later become famous, like the trumpeter Shorty Rogers and the drummer Shelly Manne. But his schoolwork at Haaren High School in Manhattan suffered, and he dropped out. He joined the Army Air Corps in 1942, became a radio operator and flew many supply missions over the Himalayas from India to China during World War II.
In 1947, he married Mildred Hurty. They had three children and were divorced in the late 1960s. In the ’70s he married and divorced Debbie Yajacovic twice. In 1985 he married Janet Valentine and adopted her daughter, Rosemary.
Besides his wife, he is survived by his son, Dale; his daughters, Donna Simpson, Jean Langdon and Rosemary Pitman; four grandchildren; and three great-grandchildren.
Mr. Pitman quit session work in 1973 and went on the road, performing in concert with Burt Bacharach, Anthony Newley, Vikki Carr and others for several years. In the late ’70s he moved to Las Vegas, where he joined the music staff of the MGM Grand Hotel, playing for headliners well into the ’80s. He also continued to play on film soundtracks until he retired in 1989.
Mr. Pitman performed professionally only once in retirement — at a memorial concert in 2001 in Pasadena, Calif., for an old friend, Julius Wechter, leader of the Baja Marimba Band. Mr. Wechter, who died in 1999, had Tourette’s syndrome and was a spokesman for people with the disorder.
Mr. Pitman continued writing arrangements, and at 99 he was still playing music — and golf.
“He plays the guitar at home just about every day,” his wife said in an interview for this obituary in 2019. “I am a bass player. We play only jazz. No rock ’n’ roll.” As for golf, she said, “He can still beat me.”