He was born in Sydney to milk vendor Terence McElhone and Catherine Mallon.
Two of his sons, William Percy (1871–1932) and Arthur Joseph (1868–1946), each served as Lord Mayor of Sydney.
[1][2] A Sydney City alderman from 1878 to 1882, he was elected to the New South Wales Legislative Assembly in 1875 as the member for Upper Hunter.
[5] McElhone was defeated by Taylor in the Mudgee by-election,[6] however he was re-elected at the Upper Hunter by-election held on the same day,[7] with the Newcastle Morning Herald and Miners' Advocate reporting that McElhone had been nominated without his authority.
Associated with the Free Trade Party, he ran unsuccessfully in 1891,[3] and 1894,[9] before winning election to the seat of Sydney-Fitzroy in 1895.