Johnson left Ireland for health reasons in 1893, settling in the Transvaal. There he made his first-class debut in the 1893–94 season, playing two matches for the Transvaal team in the Currie Cup. Shortly afterwards, he was selected for the South African team to tour England in 1894. 24 matches were played on the tour, none of which were first class. Johnson scored 508 runs at an average of 14.32 and took 50 wickets at an average of 17.27. His best scores were 112 against Liverpool and District and 79 against the Gentlemen of Ireland.[1]
Johnson made his only Test appearance for South Africa in March 1896, when he played against England at the Old Wanderers ground, Johannesburg. Having taken 0/57 in the first innings, he then scored 3 and 7 as South Africa followed on and lost by an innings.[2]
Johnson died at Maraisburg, Roodepoort, Transvaal, on 31 May 1908, aged 37.[3]