Stewart played in his first Australian Open in September 1909, at Royal Melbourne. He finished 36 strokes behind the winner but was the second South Australian, 4 strokes behind James Scott, the Adelaide professional. The 1910 Open was held at Stewart's home club, Adelaide Golf Club, the first time it had been held in South Australia. A 36-hole event for professionals was held on the day before the Open started, Stewart finishing second behind Dan Soutar. In the Open itself he finished tied for 8th place, the third professional and the leading South Australian. Stewart didn't travel to Sydney for 1911 Open but played again at Royal Melbourne in 1912. He was third after the first day but finished in a tie for 7th place. The 1913 Open was again played at Royal Melbourne. Stewart was tied for second place after the first day. He needed a 5 at the final hole to finish third and take the £10 prize as the leading professional. However he took 9 and finished 6th, 3 strokes behind Dan Soutar. Two 36-hole professional events were played on the Royal Melbourne course after the Open, Stewart finishing joint runner-up in the first and runner-up in the second, behind Soutar on both occasions.
