Johnston was born in 1889 in Bulli, New South Wales to Isabella and John, and moved to Cardiff at the age of nine.

He worked in the Newcastle Electric Supply Department for 40 years, and at one point was its commercial superintendent.

[1] Johnston played for West Wallsend and was a foundation member of the Cardiff Soccer Football Club.

In 1950, he was manager of the Australia national soccer team for one game against a Western Australian representative side, with Harold Barwick.

Johnston was a member of the Lake Macquarie Shire council for about 35 years, from approximately 1915 to 1950, when he did not seek reelection.