[7] Frederick emigrated to Australia by the Ceylon in 1844 and was shortly after employed on William Charles Wentworth's massive Murrumbidgee River station Tala (also known as Yanga) where he served as superintendent.

[10] On 18 August 1848 he was appointed "Magistrate of the Territories and its Dependencies" and Commandant of newly established Native Police Force[11] on the recommendation of his former employers William Charles Wentworth (1790–1872) and Augustus Morris (1820?–1895), both members of the New South Wales Legislative Council.

[12] Walker had attracted attention, it was later stated, by his capacity to engage local Aborigines, understand their culture, speak their language and use this to secure peaceful coexistence between them and the white settlers.

[15] The Native Police Force that Walker was to command was formed in August 1848 in the Deniliquin area on the Edward River and commenced training later that year.

Fourteen 15- to 25-year-old Aboriginal troopers were picked from four different Murrumbidgee tribes, by all accounts a well drilled and highly disciplined band greatly committed and attached to their Commandant who remained exceedingly proud and protective of his men.

Governor Fitzroy noted in the 1851 end of year report "that a great many blacks were killed," however no official action was taken to change the aggressive functioning of the force.

[20] When the first overlanding pastoralists entered the Port Curtis area, the 1st Division of Native Police under Commandant Walker was sent into the region to "have a month's sharp shooting.

[24] Further official complaints to the government in Sydney of massacres of peaceful "station blacks" by the Native Police were brushed off in parliament by the Attorney-General as unfounded or exaggerated.

[25] Embarrassing information like these reports and further complaints from squatters, such as William Forster, who felt they didn't get enough protection from the force, as well as certain financial irregularities, pushed the NSW Government into organising an inquiry into the Native Police.

The troopers were denied entry, and after an attempt to continue with proceedings, the inebriation of Walker forced an adjournment to the inquiry which was later quickly and conveniently abandoned altogether.

Walker received two severe spear wounds and with difficulty made his recovery at nearby Palm Tree Creek station owned by squatters Scott and Thompson.

Walker recruited ten of his ex-Native Police troopers and formed a private militia that roamed the Dawson River area conducting punitive missions against local Aboriginal groups.

The troopers were actively recruited from the discharged members of the Native Police and were financed by local squatters unhappy with the government run force.

He found that Walker's troops were conveniently already dissolved and working on Andrew Scott's Hornet Bank and Pollet Cardew's Eurombah stations as shepherds earning £35 per annum.

[33] He expanded his property interests in 1860 by establishing the Planet Downs station on the Comet River with Daniel Cameron, and helped Rolleston and the Dutton brothers take up their runs nearby.

This strategy went against official Queensland Government policy at the time which encouraged the forcible removal or elimination of Aboriginals from desirable frontier grazing lands.

Walker wrote letters to the Attorney-General complaining of the actions of Lieutenant Patrick of the Native Police killing peaceable Aboriginals on his run.

[34] He also described how magistrates in the area viewed the "native blacks" as aliens in their own land, legally voiding them of any rights and refusing to prosecute white people who had murdered them.

[35] Around this time, Walker was also commissioned by a Sydney pastoral company to locate a suitably large area of land to graze 100,000 head of sheep.

In 1866, Walker was employed by the Superintendent of Electric Telegraph to survey a 500-mile route from Bowen to Burketown in a bid to compete against South Australia for the end of the Trans-Oceanic link from Europe.

Although the South Australian project won the race and Darwin became the terminus, Walker did manage to lead an expedition to survey a route for the Burketown line.

The entry in H.E.Young's journal recorded Walker's passing: "as soon as the horses were brought up and a couple saddled, Perrier and Ewan were starting for the doctor of the Leichhardt search expedition which was camped about six miles off.

The inscription reads:[41] On August 17 1848 Frederick Walker, aged 28, was appointed to the position of Commandant of the Corps of Native Police having emigrated from Australia from England.

After his dismissal he continued to live on the frontier and briefly formed an illegal force of ten ex-troopers from the Native Police Corps to protect settlers in the Upper Dawson region.

[42] The original letter[43] from Frederick Walker to the Colonial Secretary regarding an attack of the Native Police on "Friendly Blacks" at a station in Central Queensland, killing and wounding several of them.