Johnston started to play tennis in early 1906, aged 11, on the public asphalt courts in Golden Gate Park.

After the 1906 San Francisco earthquake, the schools were closed, and he spent much of his spare time practicing on the tennis courts.

[6] Until "Big Bill" Tilden began to defeat him regularly in 1920, Johnston had been the best American player for a number of years and was ranked No.

[7] In July 1919, Johnston defeated Tilden in the final of the U.S. Clay Court Championships.

Together Johnston and Tilden won seven consecutive Davis Cup trophies, from 1920 to 1926, a record that still stands.

[10] In September 1927, Johnston announced his retirement after the U.S. Davis Cup loss to the French team consisting of the 'Four Musketeers' and confirmed his decision in mid-1928.