Stewart was born in Azamgarh, in the United Provinces of India, and educated at Wellington College in England, where he captained the First XI.
He served as an officer with the British Army in South Africa, and represented King William's Town, where he was stationed, in the Champion Bat Tournament.
In the 1879–80 tournament he was the leading batsman; in the low-scoring final he scored a century and took seven wickets in King William's Town's innings victory over the team from Port Elizabeth.
[1] In the next Champion Bat Tournament, in 1884–85, he top-scored for King William's Town in all three matches.
[4] Stewart served with the Cape Mounted Riflemen in Basutoland in 1880 and was awarded a medal with clasp, and later served in the Second Boer War, for which service he was awarded the Queen's South Africa Medal with four clasps and the King's South Africa Medal with two clasps.