He was educated at Synge Street CBS before joining the civil service in 1955.[1]
Murphy served in the Department of Industry and Commerce, in the Department of Finance, and joined the newly created Department of the Public Service in 1973. He became Secretary-General of the latter in 1983. In 1987, he was appointed Secretary-General, Public Service Management and Development, at the Department of Finance, when the functions of the Department of the Public Service were transferred.
On 1 November 1994, Murphy was appointed as Ombudsman by the president, Mary Robinson, upon nomination by both Houses of the Oireachtas.[3][4] In this position, he dealt with complaints against government departments, local authorities, and other public bodies. Under the terms of the Freedom of Information Act 1997, he also held the office of Information Commissioner from April 1998.[5] The Information Commissioner may review decisions of public bodies in relation to requests for access to information.
In June 2003, Emily O'Reilly succeeded him in both posts.[9] Although Murphy retired from employment in 2002 when he turned 65, he continued in public life, including sitting on a committee to appoint members of the new Irish Press commission in 2006.[10]