The transfer of ahimsa from personal discipline to political method is a twentieth-century development, and Gandhi is the reason for it.
Gandhi grew up in Gujarat in close contact with Jain teaching; his mother's practice and an early Jain mentor are documented influences. He combined that inheritance with the Sermon on the Mount, with Tolstoy and with Thoreau, and produced satyagraha, holding to truth: the deliberate acceptance of suffering without retaliation, in order to make an opponent's use of force publicly untenable. It is a technique with rules rather than a mood. Participants were trained, required to maintain discipline under attack, forbidden to exploit an opponent's difficulty, and expected to remain willing to negotiate throughout.
Two things about it are routinely misdescribed. First, Gandhi did not present it as passivity, and stated plainly that violent resistance was preferable to cowardice. Second, its record is mixed rather than triumphal. It worked against a British administration constrained by its own domestic politics and its own press, and historians continue to argue over how much Indian independence owed to satyagraha, how much to Britain's exhaustion after 1945, and how much to other pressures including armed resistance elsewhere in the movement.
The transmission onward is well documented. Martin Luther King studied Gandhian method directly and travelled to India in 1959, and the American civil rights movement adopted the training, the discipline and the deliberate courting of visible brutality before cameras. Later movements in South Africa, Eastern Europe and elsewhere borrowed the same repertoire, generally without any of the metaphysics. The comparative point worth holding onto is that a doctrine developed to avoid harming insects became, by a traceable route through one man's reading, the standard technique of unarmed mass politics worldwide.