In Australian parliamentary practice, the Father of the Australian Parliament is the more senior of the Father of the Senate and the Father of the House of Representatives. It is an informal, honorific title which carries no parliamentary responsibilities. Where two or more parliamentarians have had equal lengths of continuous service, more than any other currently serving parliamentarian, they are known as the joint Fathers of the Parliament. The current Father of the Parliament is Senator Ian Macdonald who has held the title since 10 May 2016.
The only Father of the Parliament with broken service but whose latter period of continuous service was sufficiently long to qualify was Eddie Ward.
The first parliament was elected in March 1901. The election was held on Friday 29 March in South Australia and Tasmania, and on Saturday 30 March in the other states. Despite that slight variation in the election date, all of those elected to the first Parliament were considered to have had equal seniority. It follows that there could not be a "longest-serving parliamentarian" until only one member or Senator from the first Parliament was still serving. That occurred on 30 June 1938 with the retirement of Senator Sir George Pearce, leaving Billy Hughes as the first Father of the Parliament.
The longest serving Father of the Parliament was Philip Ruddock MP who held the title from 1 September 1998 until his retirement from the House on 9 May 2016; a total of 17 years and 251 days. In late December 2012, he surpassed the previous record-holder, the inaugural Father Billy Hughes, who held the title for 14 years, 4 months (from 1 July 1938 until his death on 28 October 1952).
Senator Macdonald is only the third Senator to hold the title with Senators Gordon Brown (1963–65) and Justin O'Byrne (1977–81) being the other two.