Johnstone was one of just six members of the umpiring group, which is primarily responsible for officiating the Women's National Cricket League and Rebel Women's Big Bash League competitions, as well as the men's national second-tier Toyota Future League.
Johnstone joins the panel with more than a decade of experience at Premier Cricket level in WA and has already officiated Domestic One-Day matches, debuting in December 2010, where he stood with fellow West Australian Mick Martell in the match between WA and Queensland at the WACA Ground.
Johnstone went on to stand in a further three One Day Domestic fixtures.
Johnstone's recent performances earned him appointments to the recent Under 19 International series between Australia and Sri Lanka in Hobart, while his past 12 months also included WBBL and Futures League appointments.
His resume also includes five Under 19 and one Under 17 Men's National Championships.
Off the field, Johnstone is an active member of the WA Cricket Umpires Association, sitting on the committee of management and having served as secretary for two seasons.