Wills was first cousin of Henry Thomas Dundas Le Vesconte, an English Royal Navy officer and polar explorer who died on the Franklin Expedition in 1845.

[3] Wills bought a share in the Melbourne Gold Mining Company in 1852 and planned to migrate to Australia with his wife Sarah and sons William and Thomas.

Eighteen-year-old William and fifteen-year-old Thomas departed from Dartmouth on 1 October 1852 aboard the Janet Mitchell, and they arrived in Melbourne on 3 January 1853 with 197 other passengers.

In February 1853, the Wills brothers found work as shepherds at a property owned by the Royal Bank Company on the Edward River near Deniliquin.

In the same year, their father followed his sons to Australia, arriving in August 1853, and the three returned to Melbourne before moving to Ballarat where William John Wills worked as a digger in the goldfields.

In November 1858, he received a temporary appointment on the recommendation of Charles Whybrow Ligar, Surveyor General, as a supernumerary at the recently established Magnetic Observatory which was then located at Flagstaff Hill.

The expedition left Melbourne on Monday, 20 August 1860 with a total of 19 men, 27 camels, and 23 horses, and they reached Menindee on 16 October 1860, where Landells resigned following an argument with Burke.

Burke, Wills, John King and Charley Gray reached the mangroves on the estuary of the Flinders River, near the current town Normanton, Queensland, on 9 February 1861, though flooding rains and swamps meant they never saw open ocean.

Already weakened by starvation and exposure, progress on the return journey was slow, and the group was hampered by the tropical monsoon downpours typical to the wet season.

In 1862, Howitt returned to Cooper Creek and disinterred Burke and Wills' bodies, taking them first to Adelaide and then by steamer to Melbourne where they were laid in state for two weeks.