Thomas Arnold was an Orientalist scholar and administrator. From 1888 to 1898, Arnold taught philosophy at the Muhammad Anglo-Oriental College in Aligarh. His contemporaries were Theodore Morison (chair of the report into scholarships for Indians to study technical subjects in the UK in 1913) and Theodore Beck, the Principal of MAO college.
In 1898, Arnold joined the Indian Educational Service and taught philosophy at Government College, Lahore, where he had a profound influence upon the poet-philosopher Mohammad Iqbal. Arnold returned to London in 1904. He worked as assistant librarian at the India Office, and taught Arabic at University College, London.
In 1892, Arnold married the niece of Theodore Beck. Theodore Beck's sister, Emma Josephine Beck, was Honorary Secretary of the National Indian Association from 1905 to 1932. In 1910, when the NIA's offices were housed in 21 Cromwell Road, so were the offices of the Bureau of Information for Indian Students for whom Arnold acted as educational advisor to Indian students (1909-12). Arnold was also involved in the formation of the India Society in 1910. In 1920, he retired from the India Office and was appointed as the first holder of the School of Oriental Studies' (founded in 1917) chair of Arabic and Islamic studies.