Wisdom was born in Blackburn, Lancashire, England, and arrived in Australia in 1834 with his parents, moving to Morpeth in the Hunter Valley.[2] He was educated at Maitland and at the Sydney College.[2] In November 1858 he was appointed a clerk of petty sessions at Stoney Creek,[3][a] before being appointed a sub-commissioner of gold fields,[4] and a magistrate.[5]
Parliament was dissolved in November 1874 and Wisdom agreed to be a candidate for the district of Morpeth,[11] winning the seat in 1874.[12] He was appointed a member of the Council of Education 1878.[1] In March 1875 Wisdom was nominated to be the Speaker of the Legislative Assembly but was defeated by a single vote.[13] After declining numerous offers of ministerial positions,[14] he agreed to be Attorney General in the Third ministry of Sir Henry Parkes from August 1879 to January 1883.[2][15] He personally prosecuted the Watabadgery bushrangers, Captain Moonlite and Thomas Rogan, which drew praise from the Bulletin for his forensic skills.[16] In 1885 he was involved in an altercation with David Buchanan, initially exchanging insults before Wisdom struck Buchanan in the face.[1][17] He was made a Queen's Counsel in 1886,[18] and decided not to contest the 1887 election.[1]
He was appointed to the Legislative Council in February 1887, shortly before leaving for England with Sir Patrick Jennings as one of the delegates of New South Wales, to the first Colonial Conference.[2] Returning to New South Wales as Sir Robert, he did not take his seat in the Legislative Council before he died on 16 March 1888(1888-03-16) (aged 58).[1][15]