As Society president, Besant expanded Theosophy's public reach considerably, writing prolifically on its doctrine, including Esoteric Christianity (1901), which reread Christian scripture and ritual through a Theosophical framework of hidden inner teaching, and collaborating closely with Charles Webster Leadbeater on Thought-Forms and other clairvoyant investigations, defending him through repeated controversies over his conduct that threatened to split the Society. Together the two also promoted the young Jiddu Krishnamurti as a prophesied World Teacher, a project that consumed much of the Society's energy in the 1910s and 1920s before Krishnamurti himself repudiated the role in 1929.
Alongside her Theosophical leadership, Besant became deeply engaged in Indian politics, settling in India, founding Central Hindu College at Benares, and campaigning for Indian self-government through her Home Rule League. In 1917 she was elected president of the Indian National Congress, an unusual position for a British born woman to hold, reflecting the seriousness with which Indian nationalists had come to regard her advocacy. She continued both her Theosophical and Indian political work until her death, embodying, more than any other single figure, the movement's claim to bridge Western esoteric interest and genuine engagement with Asian religious thought.