He commanded Armed Constabulary posts in the Waikato region for a number of years and was present at the 1881 occupation of Parihaka.

When that came to a conclusion, he then fought in Te Kooti's War in the Bay of Plenty and was involved some of the engagements of the invasion of the Ureweras.

The Armed Constabulary entered the village, its population boosted by the presence of protesters, on 5 November and Newall was one of the officers to arrest the ringleaders.

[4] Newall's duties included the training of units of the Volunteer Force., the part-time component of the New Zealand Military Forces.

Colonists were concerned enough to fear for their safety and a party of 120 men, under the commander of Newall, were sent to Waimea, on the Hokianga, in early May.

Eventually, what became known as the Dog Tax War was settled with the arrest of the ringleaders and Newall's men were not called upon to take action.

[5][6] In March 1900 Newall led the 5th Contingent to South Africa, where for the next nine months it campaigned as part of New Zealand's contribution to the Second Boer War.

[1] His command was organised as four squadrons of mounted infantry and, forming part of the Rhodesian Field Force, was involved in several skirmishes with Boer commandos, including one on 5 September, in which a patrol of troopers led by Newall captured several prisoners of war.

Mentioned in despatches during the campaign in South Africa, Newall was subsequently appointed a Companion of the Order of the Bath in recognition of his services there.

[1][5] Still in good health, Newall was called upon in October 1913 to lead a group of special constables to help maintain order in Wellington during the Great Strike that arose at that time.