He was educated at Eton and Street John"s College, Cambridge.
He was elected to the House of Commons for New Romney in 1785, a seat he held until 1790, and then represented Steyning from 1794 to 1802. In 1803 he succeeded his father as second Baron Henniker but as this was an Irish peerage it did not entitle him to a seat in the House of Lords. He instead returned to the House of Commons as the representative for Rutland in 1805, which he remained until 1812, and then sat for Stamford between 1812 and 1818.
In 1792 he assumed by Royal licence the additional surname of Major.
Royal Society; 1st United Kingdom Parliament. 2nd United Kingdom Parliament. 3rd United Kingdom Parliament.
4th United Kingdom Parliament.
5th United Kingdom Parliament. 16th Parliament of Great Britain.
17th Parliament of Great Britain. 18th Parliament of Great Britain.