He was called up for service in militia during the Second Taranaki War and was posted to the Whanganui Native Contingent (WNC) as the unit's quartermaster.

[6] The following month, Austin's detachment was sent to New Zealand, in response to a request from its governor, Sir George Grey, for British troops to assist in putting down unrest in the country.

[10] On 30 May 1851, Austin married Lavinia née Newport, the daughter of an English settler and his wife, at the mission church in Putiki.

[19][20] He was involved in an attack on Weraroa pā, held by the Hauhau, on 21 July, leading a party of WNC although it was largely empty by the time they arrived.

[22] The WNC was later involved in a followup campaign in the Taranaki from August to November, led by McDonnell, and the hunt for Kereopa Te Rau, who had murdered the missionary Carl Völkner at Ōpōtiki in March 1865 and who was hiding in the Urewera ranges.

[27] Returning to civilian life, Austin performed labouring work in Whanganui but struggled for money and had to mortgage his house in October 1872.

The medal was originally limited to military personnel of the British Army and Royal Navy who had served in New Zealand but in 1869, eligibility was extended to the colonial militia.

The Defence Department did not agree with him and declined to issue another medal, which remained a sore point with Austin for the rest of his life.

[29] The following year, Austin was nominated by Keepa for an award of the New Zealand Cross (NZC) for his service during the campaign in the Taranaki and the fighting against Te Kooti.

[30] The NZC was instituted in 1869 to recognised acts of gallantry performed by the country's colonial military forces and four years later, nominations were invited for scrutiny by a commission.

[31] Keepa's efforts to have Austin receive the NZC were supplemented by Major McDonnell, who wrote to the Secretary of Defence explaining the events that occurred at Keteonetea.

[30] The citation for Austin's NZC, published in the New Zealand Gazette, read: For gallant and distinguished conduct on the 7th January, 1866, when, at the capture of the Putahi Pa, Lieutenant Colonel McDonnell was severely wounded and Sergeant Austin carried him during a great part of the engagement under raking fire, and finally off the field, which action was witnessed by General Chute, who then thanked him for his fearless and heroic conduct not only in this instance, but on all occasions during the campaign on the West Coast.

Also on 17th October, 1866 at the capture of the village of Keteonetea, Captain William McDonnell leading a small advance guard of Maoris, came upon an ambush, and fell severely wounded; his men leaving him, retired on the main body, who commenced to retreat, when Sergeant Austin, assisted by another man (since dead), returned to where Captain McDonnell lay, on the point of being tomahawked by the enemy, and at all risks carried him off under a heavy fire.Austin was presented with the NZC in March 1876 in a ceremony at Wanganui, with Keepa and Thomas Adamson also being awarded the medal at the same time.

[31] In late 1876, he began to receive a daily allowance as an out-pensioner, qualifying as a result of his service with the 65th Regiment, from the Royal Hospital at Chelsea; this amounted to £6 a year.

Life became easier for Austin, who was no longer labouring but instead was selling vegetables grown on land surrounding his property while his wife worked as a midwife.