Cecil Charles Harpur Baldwin was born at Rydalmere, New South Wales, in 1893, the grandson of Australian poet Charles Harpur. Preceding his First World War service he was a member of the senior cadets and the militia units St George's Rifles and the Legion of Frontiersmen. The 22-year-old clerk and accountant enlisted with the Australian Imperial Force on 16 August 1915, and he departed Sydney with reinforcements for the 18th Infantry Battalion aboard HMAT Suevic on 20 October 1915.

In February 1916 Baldwin was transferred to the 3rd Infantry Battalion, which was sent to the Western Front. Among his regular duties, he wrote of listening in the trenches at night for enemy movement and patrols. He wrote to his mother several times during his time on the front, taking great effort to portray a positive experience as to mitigate her worrying. Baldwin signed off most of these letters with the phrase, "Don't worry, be happy." The battalion's first major action in France was at Pozières in July and August of 1916. There Baldwin was awarded the Military Medal for bravery in the field during the battle. In November he was wounded in action with a gunshot to the left arm.

On 1 March 1917 Cecil Baldwin was killed at La Barque near Bapaume during an early morning raid by a Prussian Guards unit. He was killed instantly by a sniper's bullet as he emerged over the parapet of his dugout. Baldwin was described by his fellow B Company soldiers as being a "very fearless man" and "one of the bravest men that ever stood". He is buried in France at the Warlencourt British Cemetery.