Upon the outbreak of the First World War in 1914, Chelmsford came India to serve as a captain in the Dorsetshire regiment.
During the early part of World War I (1914–18) he received quick promotions, to the surprise of many, and was named viceroy in 1916.
He undertook, with Edwin Samuel Montagu, the secretary of state for India, a study of the India’s political situation that became known as the Montagu-Chelmsford Report, which was presented to Parliament in 1918 and became the basis of the Government of India Act of 1919.
He served as Governor General and Viceroy of India from 1916 to 1921. Important events during his tenure included;
- Lucknow Session and Lucknow Pact 1916
- Montagu Declaration 1917
- Indian Constitutional Reforms Report {Montague-Chelmsford Report}
- Government of India Act 1919 {Mont-ford Reforms}
- Rowalt Committee 1918 and Rowlatt Act, 1919
- Satyagraha Movements
- Jallianwalla Bagh tragedy, 1919
- Disorders Inquiry Committee {Hunter Committee}
- Khilafat Movement
- Non-Cooperation Movement, 1920-22