The Johnsons owned a magnificent property, "St Catharine's" in Prospect, later the administration centre of Blackfriars Priory School.
[4] In December 1902 Johnson was elected to the Adelaide City Council to represent the Hindmarsh ward, but almost immediately required three months' leave of absence to visit Germany with his wife, whose mother was ill.[5] He resigned a year later, in advance of another trip to Europe.
[3] He was at the time also: He was a man of strong opinions, and took a contrary stand against his colleagues on several issues:[4] He was skeptical about the effectiveness of Pasteurella bacteria in the control of rabbits as proposed in 1905 by Professor Danysz, and which had been elsewhere been greeted enthusiastically.
[7] He argued in 1937 against diphtheria immunization on the grounds that it was effective against the milder forms of the disease but might promote the more dangerous gravis strain.
[8] Concern was raised that his outspokenness might prompt parents to withdraw consent to a measure that had been proved both safe and effective.