Biography.guide
Home › People › Businessperson › James Macmahon
Portrait of James Macmahon

James Macmahon

1865 – 1954

Irish civil servant and businessman

Don't just read it — keep itBiographies to ownE-book · Audio · Video From $7 →

About James Macmahon

Lived 1865 – 1954 (aged 89). James Macmahon was a British and Irish businessperson.

James Macmahon PC (Ire) (20 April 1865 – 1 May 1954) was an Irish civil servant and businessman.

Macmahon was born in Belfast and raised as a Roman Catholic. He was educated at St Patrick's College, Armagh and Blackrock College in Dublin. He joined the Irish Post Office, being promoted to Assistant Secretary in 1913 and Secretary in 1916. In 1918, he became Under-Secretary for Ireland.

There was a need to decode the coded messages sent to the Dublin Castle administration from London. Macmahon appointed GPO worker Nancy O'Brien due to her dedication and purported lack of interest in politics. However, O'Brien was a second cousin of Michael Collins, and each day, between 2:30 and 3:30, she would pass any salient information she acquired to either Joe McGrath, Liam Tobin or Desmond FitzGerald.

Macmahon was appointed to the Privy Council of Ireland in the 1920 New Year Honours, entitling him to the style "The Right Honourable". He remained Under-Secretary until his retirement on the formation of the Irish Free State in 1922. He went into business in Dublin. In 1947, he was elected president of the Royal Dublin Society. He died on 1 May 1954, aged 89.

Footnotes

Biography shop

Don’t just read it —
keep it.

Full-length biographies made to live with: read them, listen on the way to work, watch them tonight.

  • E-book
  • Audio
  • Video
Browse the shop — from $7

Instant download · yours to keep · every purchase keeps this site free

Important facts

Birth century
Died
Occupation
Education
Blackrock College
Positions held
Member of the Privy Council of Ireland, Under-Secretary for Ireland

People in James Macmahon's life

Named in this biography and alive at the same time

Contemporaries

People whose lives overlapped James Macmahon's

Frequently asked questions

Who was James Macmahon?

Irish civil servant and businessman (1865–1954)

When was James Macmahon born?

James Macmahon was born on 20 April 1865 in Belfast.

When did James Macmahon die?

James Macmahon died on 1 May 1954.

What was James Macmahon's occupation?

James Macmahon was a businessperson.

What nationality was James Macmahon?

James Macmahon was British and Irish.

Sources & further reading

· Wikipedia: James Macmahon

· Wikidata: Q6138726

· DBpedia: James Macmahon

Cite this page

APA: Biography.guide. (2026). James Macmahon. https://biography.guide/james-macmahon/

MLA: "James Macmahon." Biography.guide, https://biography.guide/james-macmahon/.

Chicago: "James Macmahon." Biography.guide. https://biography.guide/james-macmahon/.

Data last updated: 2026-09-20 · Spot an error? Report a correction.

Page generated 2026-09-27 05:01 UTC