While working as a professional at the Midlothian Country Club, near Chicago he won the fifth staging of the U.S. Open in 1899, which was played at the Baltimore Country Club, Roland Park Course. He won by a margin of eleven shots, which wasn't bettered until Tiger Woods won the 2000 championship by fifteen shots. Smith's prize was $150. He played in nine U.S. Opens in total, and made the top-10 in eight of them, but he did not win again.
In 1904, Smith moved to Mexico City to become the golf pro at the Mexico City Country Club. He was injured during the Mexican Revolution. He had refused to leave his post at the country club and was found trapped under a fallen beam after Emiliano Zapata's troops ransacked the club which they saw as a symbol of the corrupt ruling class. He later died of pneumonia. His body was returned to Scotland for burial in the family plot.