I assume you mean Mahatma (there were also other relevant Gandhis: Indira, Sonia)
Some important events in his life were:
-his time in Jail in South Africa, which made him sensitive to racism
-his involvement in the Boar War when he was an ambulance driver
-1920 Gandhi took leadership of the Indian Congress Party
-his non-cooperation movement starting in 1921
-Indian independence in 1947