Leslie Bowles was born in Sydney in 1885. He began his studies at the Brisbane Technical College in modelling and woodcarving, and in 1910, won a McConnell scholarship and travelled to London. While in England, he studied at the South London School of Sculpture and the Royal Academy School and became an assistant to Betram MacKennal, another expatriate Australian sculptor working in England.
Bowles enlisted in the 25th London Regiment in 1914, and the same year transferred to the Royal Tank Corps, with whom he served in France until 1919. After the war, he returned to England and resumed his study at the Royal Academy. In 1923, he entered the competition to design a memorial to the Australians and New Zealanders who fought in the Desert Mounted Corps in Port Said, Egypt. Bowles' design was awarded 3rd place in the competition, which was won by Charles Web Gilbert.
On returning to Australia in 1924, Bowles was employed by the Australian War Memorial on the production of dioramas depicting significant events from the First World War. He worked in the modelling section with a team of other artists, including Charles Web Gilbert and Wallace Anderson.
After Gilbert's death in 1925, Bowles became head sculptor of the modelling section at the Memorial, and remained in this position until 1931. His work also included the supervising the repair, and casting in bronze, of figures previously modeled by Gilbert, modelling heads of diverse nationalities for mannequins used to display military uniforms, and designing the gargoyles in the commemorative courtyard. Bowles produced several sculptures for the Memorial, including The man with the donkey, a memorial to Simpson and his donkey. With Napier Waller, Bowles also designed the initial sculptural feature for the Hall of Memory.
He was also often called upon for advice on the commissioning of sculptures and memorials right up until his death in 1954.