Mildred was born in Portsea, Hampshire, England. Trained as a shipbuilder, he was contracted by the South Australian Company on the South Australian with David McLaren, arriving at Kangaroo Island on 22 April 1837, to manage the purchase and loading of major machinery which was ultimately used for "Fletcher's Patent Slip", for the Company's flour mill, eventually installed on the Torrens where the Hackney Hotel is now, and for a sawmill which may have been used at Cox's Creek. Mildred was invited to get this equipment running but he demurred, and it lay idle for some time. Shortly after arrival on Kangaroo Island, Mildred, T. H. Beare and William Giles imported a batch of Merino ewes from Van Diemens Land, some of the first brought into the colony, though stock losses on the unusually long trip aboard the were considerable. The land he selected, on Fourth Creek, and where he lived for the rest of his life, turned out to be quite valuable, and made his fortune.
Politics
He served on the Adelaide Municipal Council from 1841 to 1843. He was one of the colonists who strenuously opposed bringing out boys from the Parkhurst prison. He contested the election for the Legislative Council seat of Burra without success, but in 1850 was appointed to the Main Roads Commission and later that year appointed Justice of the Peace, and in 1858 made a Special Magistrate. In 1851 sat for, but failed to win, one of the first elected positions on the Legislative Council. He represented Noarlunga in the first House of Assembly from 1857 to 1860, East Torrens from 1860 to 1865, and held a seat in the Legislative Council from 1866 to 1871. He was appointed a member of the Central Road Board Committee in March 1858 and was appointed Special Magistrate in November 1858.
Family
He was married to Elizabeth Sarah, née Bowyer, and had three sons and two daughters:
Clarissa Martha Margaret Mildred married Captain Henry Hay on 23 April 1840
Hiram Telemachus Mildred preceded his father to South Australia on the Rapid. He was elected to the City Council, was later Harbourmaster at Port Augusta.
Henry Hay Mildred represented East Torrens from March 1870 to December 1871.
He died at the home of Dr. Mortimer, Port Adelaide. Henry's brother George Mildred, arrived in South Australia in 1836 on William Light's ship Rapid with nephew Hiram and settled on Kangaroo Island.
