Career
He began his political career at the municipal level, serving as an alderman in the City of Saint James (now part of Winnipeg) from 1964 to 1966, and in the successor city of Saint James-Assiniboia from 1968 to 1972. He was chosen as the city"s deputy mayor in 1968, and also chaired the urban renewal committee. Johnston was first elected to the Manitoba legislature in the provincial election of 1969, defeating Liberal Robert Chipman by 530 votes in the Winnipeg riding of Sturgeon Creek.
In the 1973 election, he was re-elected with an increased majority.
Johnston was re-elected again in the 1977 election, in which the Progreson a majority government. From October 24, 1977 to October 20, 1978, he was a Minister without Portfolio responsible for the Manitoba Housing and Renewal Corporation.
On October 20, 1978, he was promoted to Minister of Economic Development. On November 15, 1981, this portfolio was changed to Economic Development and Tourism.
The Progressive Conservatives were defeated in the 1981 election, and Johnston was re-elected with a reduced majority.
He was re-elected in the 1986 election, but ironically lost to Liberal Iva Yeo in the provincial election of 1988, just as the Progressive Conservatives formed a minority government under Gary Filmon. He has not sought a return to political life since this time. Johnston was an aggressively partisan Modern Language Association, and frequently referred to New Democrats as communists in legislative debates.