He spent his entire professional playing career with Blackpool, with whom he appeared in three FA Cup Finals, winning one.

Three years later, on 20 November 1937, he made his debut in a 2–0 defeat to arch-rivals Preston North End at Deepdale.

[1] Johnston was inducted into the Hall of Fame at Bloomfield Road, when it was officially opened by former Blackpool player Jimmy Armfield in April 2006.

In February 1970, he became assistant secretary, a role that meant he was in charge of the ticket office and editing the club's programme.

[2] When he died in his hometown of Manchester in 1973 at age 54, "the whole town of Blackpool mourned, for Harry Johnston was one of the greatest players ever to wear the tangerine shirt.