James Archibald ('Jumbo') Morrison was the second son of Alfred Morrison (1821-1897) of Fonthill House, Wiltshire. His elder brother Hugh (1868-1931) inherited Fonthill House and Islay House and was the ancestor of the Barons Margadale.
James Morrison was educated at Eton and at New College, Oxford, where he excelled at rowing, twice being on the winning crew against Cambridge. In 1891 he had joined the 4th (Eton Volunteer) Batallion of the Oxfordshire Light Infantry as a second lieutenant, but in 1895, on leaving Oxford, he joined the regular army. He was made a lieutenant in the Grenadier Guards in 1898. He fought in the Sudan, and between 1899-1900 was in the special service in the Boer War in South Africa. Morrison left the army in 1900, but rejoined the 1st Battalion Grenadier Guards on the outbreak of war in 1914. He was badly injured at the Battle of the Somme. He was invalided out of the army but was promoted to Major and received the D.S.O.
In 1900 Morrison was elected as Conservative M.P. for Wilton. He lost his seat in 1906 but in January 1910 was re-elected to Parliament as the Unionist member for East Nottingham. His obituary in 'The Times' states that 'he won a remarkable victory, defeating Sir Henry Cotton by 152 votes'. Morrison increased his majority in the general election of December 1910. The defeated Liberal Party raised a petition alleging corruption in the election campaign, but this was dismissed in May 1911. Morrison was a popular M.P., and 12,897 penny subscribers from the constituency presented him with a replica of the Warwick Vase in June 1911 as a testimonial of their esteem. Poor health led Morrison to resign the seat in 1912.
In 1910 Morrison inherited Basildon Park in Berkshire from his uncle Charles. After his resignation as an M.P. he dedicated most of his time to improving the Basildon estate. He took a great interest in farming, and enjoyed shooting and fishing. Morrison also inherited the Malham Tarn estate in Yorkshire in 1921. He sold the Basildon estate to Sir Edward Iliffe in 1929 and died in 1934.
Morrison's first wife Mary Hill-Trevor (d 1962) was the daughter of Arthur Edwin Hill, 1st Baron Trevor of Brynkinalt. They had a son and two daughters before divorcing in 1913. Morrison married secondly Gwendoline Phyllis Talmage in 1931.