He made his first-class debut for Scotland against Warwickshire at Edgbaston in June 1969, scoring 51 and 6 in a thrilling four-run Scottish victory.
Stewart played eight first-class matches in 1971, the most of any single season in his career, although he averaged only 18.
His 1972 and 1973 summers were similarly unconvincing, although he did make a match-winning 62 in a List A game against Glamorgan late in 1972 and a first-class career-best 69 against the New Zealanders in April of the following year.
He left Worcestershire after the 1973 season, and played exclusively for Scotland for the remainder of his career, captaining the side against Ireland in Clontarf, and hitting 53 and 10 in a victorious Scottish performance.
His final first-class appearance was in the same fixture at Dublin two years later, though on this occasion he scored only 0 and 11, and Scotland lost by seven wickets.