In 1874, he took up sheep farming with his brother Frank at Yuin in the Murchison district, before returning to Bowes in 1877 to lease and manage it.

[1] In 1881, Wittenoom purchased the Geraldton station White Peak from John Drummond, and established a sheep stud farm there.

On 30 May of that year he was elected to the Legislative Council's Geraldton seat in a by-election occasioned by the resignation of Maitland Brown.

On 19 December of that year he was appointed Minister for Mines, Education, and Posts and Telegraphs in the Forrest ministry.

The following month he was appointed Agent General for Western Australia in London, a position that he held until 1901.

[1] On returning to Western Australia, Wittenoom was again elected to the Legislative Council on 12 May 1902, this time for the North Province.

[2] He returned to state politics in the following election, winning a North Province seat in the Legislative Council on 13 May 1910.