O'Brien was the 19th Accountant General and Controller of Revenue of British Ceylon. He was appointed on 18 October 1890, succeeding W. H. Ravenscroft, and held the office until 31 July 1891.
O'Brien held the position of Accountant General and Controller of Revenue for British Ceylon from October 18, 1890, until July 31, 1891. He succeeded W. H. Ravenscroft in this role.