On his return to India, he travelled the countryside on foot, talking and learning from the peasants. He joined the Indian National Congress turning it from a largely powerless political organisation into a mass movement with millions of ordinary peasant followers. He founded the Sabarmati Ashram near Ahmadabad which was part school, part refuge, and part headquarters for the independence movement. He came to international attention in 1930 with the Salt March which led to his first arrest and imprisonment. Time named him Man of the Year and the following year he was released from jail. The coverage brought him more supporters.

In 1942 he threatened a mass campaign of civil disobedience and was again imprisoned. India rioted so his power only grew. However whenever his followers failed to contain their violence he would atone for it with periods of fasting and self-denial. The authorities were terrified he would die in jail, and he was released after 21 months.

In 1947, after World War II, India was granted independence as Britain no longer had the will or resources to oppose Gandhi. However Britain introduced partition, dividing India into the main Hindu region and creating Pakistan, a Moslem country. This was a great disappointment to Gandhi as his lifelong aim had also been to bring together these divided religions of India. In his talks, he would quote widely from different religions to increase mutual understanding. Over a million people died in the rioting that followed partition.