It was designed by Sir Aston Webb, a British architect who was later to redesign the façade of Buckingham Palace, and was built on the site of a row of Georgian houses that were being controversially demolished one by one as it was erected.

It was owned by the Department of Agriculture and Technical Instruction, an agency of the Dublin Castle administration, and intended for use by the Royal College of Science.

Over the decades, some departments moved out to purpose-built offices, leaving the north wing for the Taoiseach, Government Secretariat and Attorney General.

In the mid-1980s, increasingly unhappy at the cramped office space,[citation needed] Taoiseach Garret FitzGerald decided to convert the entire building for government use.

[citation needed] The entrance hall is dominated by light streaming through Evie Hone's critically acclaimed stained glass window, My Four Green Fields.