Robe entered the Royal Staff Corps as an ensign in 1817, following his father, Sir William Robe who was a colonel in the Royal Artillery. He was promoted first lieutenant in 1825, transferred to the 84th Foot in 1827, transferred to the 87th Foot as Captain in 1833, brevetted major in 1841, and promoted major in 1846. He fought in the Syrian campaign of 1840-1, and was military secretary in Mauritius and Gibraltar.
Governor of South Australia
Robe was appointed as Governor of South Australia, being sworn in on 25 October 1845. He was not popular as the governor, as he attempted to carry out his understanding of the British government's requirement to charge royalties on the mineral wealth of the province. This was rejected by the elected members of the South Australian Legislative Council as a breach of faith. There was also trouble over the question of State aid to religion, which Robe favoured, but which was strongly opposed. After requesting to be relieved of the post of governor, he was posted again to Mauritius as deputy quartermaster. He was honourable and confident in his convictions, but too conservative for the fledgling colony of South Australia. He returned to England in 1848.
Aboriginal Witnesses Act
Between 1846 and 1848, Robe was responsible for the enactment of a series ordinances and amendments first enacted by his predecessor lieutenant Governor George Grey, in 1844. Entitled the Aboriginal Witnesses Act. The act was established "To facilitate the admission of the unsworn testimony of Aboriginal inhabitants of South Australia and parts adjacent". While its stated aim was to make provisions for unsworn testimony by "uncivilised people" to be admissible in court, the act made it so that the court could not base the conviction of a White man on the testimony of an Aboriginal witness alone. The act also made Aboriginal testimony inadmissible in trials that carried the penalty of death. 
Effectively, the act created a situation where settler solidarity and the law of evidence ensured that the murder and massacre of Aboriginal Australians by European colonisers could not be tried solely on the evidence of Aboriginal witnesses.
Later life and death
Robe was appointed Companion of the Order of the Bath (CB) in 1848, brevetted lieutenant colonel in 1847, promoted lieutenant colonel in 1853, brevetted colonel in 1854, and promoted major general in 1862. He was appointed Colonel of the 95th (Derbyshire) Regiment from 1869 until his death.
He died unmarried in Kensington, London on 4 April 1871. The town of Robe, South Australia is named after him.
- E. J. R. Morgan (1967). "Robe, Frederick Holt (1802 - 1871)". Australian Dictionary of Biography, Volume 2. MUP. pp. 383–384. Retrieved 5 October 2007.
- The acts:
- "Aborigines' Evidence Act (No 8 of 7 and 8 Vic, 1844)". South Australia Numbered Acts. South Australian Government. Retrieved 24 February 2019.
- "Aborigine's Evidence Act (No 5 of 10 Vic, 1846)". South Australia Numbered Acts. South Australian Government. Retrieved 24 February 2019.
- "Aboriginal Witnesses Act (No 3 of 11 and 12 Vic, 1848)". South Australia Numbered Acts. South Australian Government. Retrieved 24 February 2019.
- "Aboriginal Witnesses Act (No 4 of 12 and 13 Vic, 1849)". South Australia Numbered Acts. South Australian Government. Retrieved 24 February 2019.
- Further detail:
- Foster, Robert; Hosking, Rick; Nettelbeck, Amanda (2000). Fatal Collisions : the South Australian frontier and the violence of memory (first ed.). Kent Town, South Australia: Wakefield Press. pp. 79–80. ISBN 9781862545335.
- Foster, Robert; Nettelbeck, Amanda (2012). Out of the Silence - The history and memory of South Australia's frontier wars (first ed.). Kent Town, South Australia: Wakefield Press. pp. 161–162. ISBN 9781743051726.
George Grey, Esq
| Governor of South Australia
Sir Henry Fox Young