On 16 July 1894 Wittenoom was elected to the Legislative Council for the Central Province. On 19 December of that year he was appointed Minister for Mines, Education, and Posts and Telegraphs in the Forrest ministry. At that time, newly appointed ministers were required to re-contest their seats, so Wittenoom resigned his seat on 19 December, and was re-elected in the subsequent ministerial by-election of 16 January 1895. He retained his seat and ministerial portfolio until the general election of 28 April 1898, which he did not contest. The following month he was appointed Agent General for Western Australia in London, a position that he held until 1901.