Macfarlane was born in Aberdeen, Scotland.[1] Like many British golfers of his era, he took a position as a club professional in the United States. In 1925 he won the U.S. Open at Worcester Country Club in Worcester, Massachusetts. He tied Bobby Jones over 72 holes, with both men shooting 291. Macfarlane had set a new U.S. Open single round low-score of 67 in the second round. The two men played an 18-hole playoff and both of them shot 75. Macfarlane won a second 18-hole playoff by 72 shots to 73.
Macfarlane played in the U.S. Open 16 times, but only had one other top-10 finish. He won 21 times on the PGA Tour.
NYF = tournament not yet founded
NT = no tournament
WD = withdrew
CUT = missed the half-way cut
R32, R16, QF, SF = round in which player lost in PGA Championship match play
"T" indicates a tie for a place
† indicates the event was won in a playoff; ‡ indicates the event was won wire-to-wire; # indicates the event was won by an amateur; 1942–1945 cancelled due to World War II