[4] John Galbraith Horn was born In Edinburgh, Scotland in 1860.

[4] He competed in the men's singles events at the Wimbledon Championships in 1881 where he lost in the first round to Ernest Renshaw.

[7] At the 1882 championships he reached the second round before losing to Frank Benson.

[4] In addition he was a losing finalist at the Oxford University Champion Tournament (1882),[4] Darlington Open (1884, 1885, 1887),[4] and the West of Scotland Championships (1894).

[4] Galbraith Horn played his final singles event at the Boulogne International Championship on clay in 1893.