Butler was the son of Joshua Butler and Esther, née Lampel. In 1959, he married Stella, daughter of Harris and Leah Isaacs; they had a son and two daughters. His son died in 2008.
Butler was called to the bar in the Middle Temple, 1955. His career was interrupted by National Service; he was a 2nd lieutenant in the Royal Army Service Corps, 1956-57. He became a QC in 1975. He was a Recorder of the Crown Court, 1977-82, a Circuit Judge, 1982-97, and senior judge at Southwark Crown Court, 1984-97.
After his retirement, he was invited to conduct inquiries and produce reports into:
In August 2005, he made controversial remarks that human rights laws stood in the way of attempts to crack down on terrorists, because after the terrorist attacks on London in July, Britain was no longer in a "normal" state where human rights legislation was always beneficial.
He was a member of the MCC.