In 1927, he joined the Royal Military College Sandhurst and was commissioned as a Second Lieutenant on the Unattached List, Indian Army on 31 January 1929. After Arriving in British India he was attached to the 2nd battalion of the Essex Regiment on 23 March 1929. On 23 April 1930 he was accepted for the British Indian Army and joined the 6th Lancers, which had descended from regiments of Bengal Lancers of the British Indian Army. He saw action in the North West Frontier Province during 1930-31.
He transferred to the Army Remount Department on 21 September 1934 and was appointed permanently in early 1938, serving as the Assistant Remount Officer, Sargoda Remount Depot (1934–36). Later he served Shahpur Area (1937–38) and Shahpur Remount Depot 1939-40.
During the Second World War he was the commandant of the Indian Armoured Corps Officer Training School at Ahmednagar in India. He later rejoined the 6th Lancers and participated in the Italian Campaign, World War II. He was the second in command and in 1945 commanded 6th Lancers. During the Italian Campaign, he was Mentioned in Despatches and awarded the Distinguished Service Order.
In 1947, Ingall became the founder Commandant of the Pakistan Military Academy and continued to remain so till 1951. He was awarded an OBE by the British Government for his vital service to Pakistan by founding Pakistan Military Academy. Brigadier Ingall retired in 1951. Later he migrated to the USA. In 1982, he was appointed the Honorary Consul General of Pakistan in California, USA. His autobiography The Last of the Bengal Lancers was published in 1988.
He died on 21 August 1998.