In 1771 Blaquiere was appointed Secretary of Legation at the British Embassy in Paris, a post he held until 1772.

After representing Enniskillen for a few months in 1783, he sat than for Carlingford from 1783 to 1790, for Charleville from 1790 to 1798 and for Newtownards from 1798 to the Act of Union in 1801.

[4] Blaquiere was created a Baronet, of Ardkill in the County of Londonderry, on 16 July 1784,[5] and raised to the Peerage of Ireland as Baron de Blaquiere, of Ardkill in the County of Londonderry, on 30 July 1800,[6] for his support for the Act of Union.

Lord de Blaquiere also sat as a Member of the British House of Commons for Rye from 1801 to 1802[7] and for Downton from 1802 to 1806.

Lord de Blaquiere died at Bray, County Wicklow, in August 1812, aged 80.