Barwick was born in Monmouth County, Tasmania (now known as Monmouth Land District) on 7 March 1890 to George Arthur Sturgeon and Elizabeth Ann Barwick. He grew up on his family's property near Hobart, Tasmania, and as a young man moved to New South Wales to manage a sheep property.
Barwick joined the First Australian Imperial Force on 24 August 1914 at Randwick, New South Wales, at the age of 24, and was assigned to the 1st Battalion. He was enthusiastic about enlisting, recording in his diary that he "threw 2 or 3 somersaults" in celebration. After completing his initial training, he embarked on HMAT A19 Afric on 18 October 1914 and arrived in Egypt for training on 9 December 1914. Barwick, like many soldiers, climbed the Pyramid of Khafre and the Pyramid of Khufu, and considered the Pyramid of Khafre to be the more dangerous for climbing.
His training was completed in March 1915 and on 4 April 1915, he was among the first troops to embark for the Dardanelles. On the journey there, the soldiers were paid with Turkish currency, which Barwick said in his diary showed the confidence of success of the Allied commanders. He landed at Gallipoli on 25 April 1915, the first day of the Gallipoli Campaign. He fought in the Battle of Lone Pine and was part of the second-last group to leave Gallipoli when Allied troops were evacuated in December 1915 after what Barwick described as "one of the most glorious and [at] the same time disastrous campaigns as Great Britain ever had anything to do with".
Barwick was then posted to France, arriving in March 1916 after a brief stay in Egypt. He fought in France and Belgium from 1916–1918. During this time, he saw action at major battles of the Somme Offensive, including the Battle of Pozières and the Battle of Flers–Courcelette, and in the Battle of the Lys. His company was involved in the capture of the town of Pozières in July 1916 under a "fearful bombardment" of German shells; he was made corporal on 1 August 1916 and then sergeant in October 1916. He was sent as an instructor to Durrington Camp near Salisbury, Wiltshire, England in May 1917 and returned to France in September 1917. He was injured three times, in November 1916, April 1917 and April 1918. The third occasion was the most serious, when an exploding shell caused him severe chest injuries. He was hospitalised for 16 weeks in Birmingham Hospital, and remained in England until the end of the war recovering from his injury.
His two brothers Leonard (known as Len) and Norman Stanley (known as Stan) also served during World War I. Len enlisted on 26 October 1914 and served in the 13th Battalion and the 1st Battalion (alongside Archie). He survived the war, being discharged in September 1918 and returning to Australia. Stan enlisted on 8 July 1916 and served in the 12th Battalion. While Archie was recovering from his second injury in April 1917, he and Stan were briefly reunited. Stan was killed in action on 8 October 1917 near Remus Wood, during the third phase of the Battle of Passchendaele.
Barwick was awarded the Belgian Croix de Guerre on 19 January 1918, receiving the notification on 5 February 1918. His award was announced in his home state in April 1918, the London Gazette in July 1918, and the Commonwealth of Australia Gazette in November 1918. He was presented with his award on 13 September 1918.
He also received the British War Medal and the Victory Medal.
Barwick kept a total of 16 diaries documenting his war service, approximately 400,000 words in total. He tried to keep a daily record of his experiences, however he was sometimes forced to write entries significantly later or from notes. His diaries are noted for their detailed description of his experiences and for their style, which has been described as similar to the Boys' Own publications. His set of diaries is one of the best-known and most extensive first-hand accounts of service in World War I.
An abridged edition (approximately 133,000 words) was published in 2013.
Barwick returned to Australia in 1919, leaving England on 4 December 1918 and arriving in Australia in January 1919. He was formally discharged from the army on 30 March 1919. On his return, a welcome party was held for him at Woolbrook, New South Wales on 3 May 1919. He lived for some time in Tasmania before returning to New England. Barwick married Mona Carroll in 1930. The couple had three children, John, Judy and Tim, and lived on a property near Armidale, New South Wales. He was a justice of the peace and, during World War II, was placed in charge of the local Volunteer Defence Corps.
Archie Barwick died on 28 January 1966 at Uralla, New South Wales.
Archie Barwick was one of the six Australians whose war experiences were presented in the The War That Changed Us, a four-part television documentary series about Australia's involvement in World War I.Barwick, Archie (2013), In great spirits: the WWI diary of Archie Barwick, Sydney South, NSW HarperCollins Publishers, ISBN 978-0-7322-9718-3