Stewart established the club in the First Division with two top ten finishes before achieving second-place in the 1923–24 season, missing out on winning the title on goal average in the narrowest margin of victory in English professional football history. Stewart's Cardiff side became the first Welsh team to reach the final of the FA Cup the following season, losing the 1925 final 1–0 to Sheffield United. Two years later, he returned to the final with Cardiff where they defeated Arsenal in the 1927 final to become the only non-English team to win the competition. The club's proceeds from its cup victories were used on ground improvements which left Stewart with little funds to reinvest in the playing squad and, two years after the cup triumph, the side were relegated from the First Division. The club's decline continued with relegation to the Third Division South in 1932. When Stewart could only achieve a 19th-place finish in his first season in the bottom tier, he retired from his position to concentrate on his business interests.