He was the son of John Henniker, of London, a Russian merchant and Freeman of Rochester.
In 1782, Henniker succeeded his father-in-law as second Baronet of Worlingsworth Hall according to a special remainder.
In 1800 he was raised to the Peerage of Ireland as Baron Henniker, of Stratford-upon-Slaney in the County of Wicklow.
[4] Lord Henniker died in April 1803, aged 78, and was buried in Rochester Cathedral.
Sir Brydges Trecothick Henniker, became a Lieutenant-General in the Army and was created a Baronet in 1813.