He was educated at Loretto School and studied at the Universities of Glasgow and Edinburgh, and served in the Royal Naval Volunteer Reserve at the end of the Second World War from 1944 to 1946.
He was admitted to the Faculty of Advocates in 1951 and appointed Queen"s Counsel (Queen's Counsel) in 1965. Stewart followed a traditional career at the Bar, serving as an Advocate Depute from 1959 to 1964 and Home Advocate Depute from 1970 to 1972. He also served two non-consecutive years on the Criminal Injuries Compensation Board, from 1969 to 1970 and 1976 to 1977.
In 1972, he became Solicitor General for Scotland in the Conservative government of Ted Heath.
The Solicitor General was the junior of the two Law Officers then existing in respect of Scotland, the senior being the Lord Advocate, an office held at the time by Norman Wylie, Member of Parliament for Edinburgh Pentlands. From April to December that year, he served as temporary Sheriff Principal of Dumfries and Galloway, the post vacated by his successor as Solicitor General, John McCluskey (later Lord McCluskey).
Stewart was appointed to the Benches of the Court of Session and High Court of Justiciary, Scotland"s Supreme Courts in 1977 as a Senator of the College of Justice with judicial title Lord Allanbridge. He remained on the Bench until retirement in 1995.
Faculty of Advocates.