Rigby was elected Member of Parliament for
Castle Rising in 1745, transferring to
Sudbury at the next general election, and was initially a partisan of
Frederick, Prince of Wales. Subsequently, he transferred his allegiance to the
Duke of Bedford, sitting as Member of Parliament (MP) for the Bedford
pocket borough of
Tavistock and eventually becoming the
Bedford Whigs' permanent "man of business" in the
House of Commons. In June 1753 he wrote to Bedford enclosing the first issue of the opposition weekly
The Protester and praising it as “an extremely good preface to a political paper.” In December 1755 he became a junior minister as one of the
Lords of Trade and in 1757, he retained a seat in the
Irish House of Commons for
Old Leighlin, which he held until 1761. When Bedford was appointed
Lord-Lieutenant of Ireland in 1758, in
a time of relative peace, Rigby accompanied him as
Secretary; the following year he was appointed
Master of the Rolls in Ireland. In theory, this was a senior judicial office, but in practice, it was a
sinecure and Rigby never sat as a judge. In 1762 Rigby was seriously considered for promotion to
Secretary at War, but he preferred to remain in lucrative sinecures rather than to accept more substantive office, and instead was made in 1765 joint Vice-Treasurer of Ireland. His career was also hampered by his violent temper, which caused him to lash out indiscriminately at everyone around him, although when in a good temper he was a model of courtesy and charm. All those who knew him admitted to finding him a puzzling and contradictory character. In 1768, Rigby was transferred to perhaps the most lucrative of all government posts,
Paymaster of the Forces, which he held for the next 16 years. He took a prominent part in opposing
John Wilkes, and later led objections to a public funeral for
Pitt the Elder. When he died in 1788, he was said to have left "nearly half a million of public money". ==Wealth==