He was Member of Parliament (MP) for Carlow from 1835 to 1837, and briefly in 1839, taking his seat in the House of Commons of what was then the United Kingdom of Great Britain and Ireland.
Bruen first stood for Parliament at the 1832 general election, in Carlow Borough, but did not win the seat.
[2] He was successful on his second attempt in 1835, when he defeated Nicholas Vigors, Carlow's Liberal Repealer MP.
[2] In 1839, Maule was appointed as a Baron of the Court of the Exchequer (a type of judge), and on 27 February 1839, Bruen won the resulting by-election by 167 votes to 164.
Francis was the sixth and youngest child of Colonel Henry Bruen (1741–1795) and his wife Dorothea Henrietta Knox.