Leila Waddell was born in Bathurst, New South Wales. She taught violin from 1901-1907, and gained good reviews as a soloist.
Attracted to the bohemian world of performance, in 1906 she joined a group called The Bresicans organized by musical director and promoter Henry Hayward. The group was composed primarily of members of Hayward's own family and the Martinego family from Brescia in Italy. Through the 1890s, The Bresicans had teamed up with T.J. West's Modern Marvel Company which exhibited scientific curiosities including X-rays and Urban-Bioscope system films. Leila Waddell played for the group during their New Zealand and Australian tours of 1906-1908, and apparently found the risqué and edgy world of theatrical touring fascinating, leaving for England in 1908. She befriended noted Australian writer Katherine Mansfield, and travelled to Germany to see the Bayreuth festival with her.
In England she played with some success at Bournemouth, a popular coastal resort, joining the A∴A∴ on April 1, 1910. For the next five years she was a significant influence on Crowley and Thelema. She was the undisputed professional performer and anchor of Crowley's staged "Rites of Eleusis," in 1910 at Caxton Hall an event which gained wide press coverage and notoriety.
In 1911 she achieved some fame in the "Viennese Ladies' Orchestra," an onstage company for a revival of the Felix Doerman and Leopold Jacobson Operetta, "A Waltz Dream," at Daly's Theater in London.
By 1913 Waddell was the core of "Ragged Ragtime Girls," a musical group promoted by Crowley which played the London Opera House and Old Tivoli, before taking a summer engagement in Moscow. She travelled to the US with Crowley in 1914, and remained there for the duration of the First World War, parting amicably with Crowley in early 1916. In addition to performance, Waddell penned articles and reviews, showing a deep intelligence and quick wit. Returning to Sydney to care for her father in 1923 where she performed with various orchestras until her death in 1932.
Waddell was a magical partner of Aleister Crowley, as well as a co-author. Together they experimented with sexual magic and conducted pioneering experiments in psychedelic trance, more than forty years before Aldous Huxley's groundbreaking The Doors of Perception and more than fifty years before Dr. Timothy Leary popularized the idea in the 1960s.
Waddell's influence on the incarnation of Thelema is both immense, and undocumented. Seen as an adjunct to Crowley she was certainly a force and ideologue in her own right. Described in the Sydney newspapers in 1910 as "High Priestess, prophetess and leader generally of a new sect" Waddell's position of influence can be seen as both artistic and pragmatic. She is likely one of the first persons to perform the Gnostic Mass described in Liber XV, written by Crowley during the Moscow trip.
A partner to Crowley her indisputable intelligence makes it clear that she was more than supporter, but a significant and revered contributor to the mélange that was pre-war Thelema.