Thomas Hennessy was an Irish

Ireland

Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 Cumann na nGaedheal party politician and medical practitioner.

He was first elected to Dáil Éireann

Dáil Éireann

Dáil Éireann is the lower house, but principal chamber, of the Oireachtas , which also includes the President of Ireland and Seanad Éireann . It is directly elected at least once in every five years under the system of proportional representation by means of the single transferable vote...

 in a by-election on 11 March 1925 in the Dublin South

Dublin South (Dáil Éireann constituency)

Dublin South is a parliamentary constituency represented in Dáil Éireann, the lower house of the Irish parliament or Oireachtas. The constituency elects 5 deputies...

 constituency, after the resignation of the Cumann na nGaedheal Teachta Dála

Teachta Dála

A Teachta Dála , usually abbreviated as TD in English, is a member of Dáil Éireann, the lower house of the Oireachtas . It is the equivalent of terms such as "Member of Parliament" or "deputy" used in other states. The official translation of the term is "Deputy to the Dáil", though a more literal...

 (TD) Daniel McCarthy

Daniel McCarthy

Daniel McCarthy was an Irish politician. McCarthy was first elected to Dáil Éireann as a Sinn Féin Teachta Dála at the 1921 elections for the Dublin South constituency. He subsequently went on to support the Anglo-Irish Treaty, becoming a member of Cumann na nGaedheal when the party was founded....

.

He did not contest the June 1927 general election, but after the death of the Fianna Fáil

Fianna Fáil

Fianna Fáil – The Republican Party , more commonly known as Fianna Fáil is a centrist political party in the Republic of Ireland, founded on 23 March 1926. Fianna Fáil's name is traditionally translated into English as Soldiers of Destiny, although a more accurate rendition would be Warriors of Fál...

 TD for Dublin South, Constance Markievicz, he stood as a candidate in the by-election on 24 August. He won the election, becoming the first – and only – candidate to win more than one by-election to the Dáil.

The 5th Dáil lasted only 98 days in total, and last sat on 16 August 1927, before adjourning until October. However, it did not meet again; a second general election was held in September, and Hennessy was returned to the 6th Dáil. He was re-elected again at the 1932 general election

Irish general election, 1932

The Irish general election of 1932 was held on 16 February 1932, just over two weeks after the dissolution of the Dáil on 29 January. The newly elected 153 members of the 7th Dáil assembled at Leinster House on 9 March 1932 when the new President of the Executive Council and Executive Council of...

, but was defeated at the 1933 general election

Irish general election, 1933

The Irish general election of 1933 was held on 24 January 1933. The newly elected members of the 8th Dáil assembled at Leinster House on 8 February when the new President of the Executive Council and Executive Council of the Irish Free State were appointed....

, and retired from politics.