Knight was born in Bristol the third son of George Knight, a provision merchant of Bristol and his wife and his wife Anne Dyos, daughter of William Dyos. He inherited his father"s business in Temple Street, and became one of the most prosperous merchants in the city, and a prominent High Church member of the common council.
When mayor of Bristol he became notorious for his activities against Nonconformists. He was knighted on the visit of the King to Bristol on 5 September 1663. He had their houses watched, and took measures with Guy Carleton, bishop of Bristol, for their punishment.
In his time as mayor over 920 people were fined for indulging in liberty of conscience.
Knight took a prominent part in the reception of Queen Catherine of Braganza in 1677. He was re-elected Member of Parliament for Bristol in the two elections in 1679 to the First and Second Exclusion Parliaments and lost his seat in 1681.
In 1680, because of poor health, he resigned from the common council. In August 1680 he acted as emissary from William Bedloe, the false witness of the Popish Plot to Chief Justice North.
Knight married Martha Cole, daughter of Thomas Cole.
Cavalier Parliament. Exclusion Bill Parliament. Habeas Corpus Parliament]
In 1660, Knight was elected Member of Parliament for Bristol in the Convention Parliament and was re-elected in 1661 for the Cavalier Parliament.
His intolerance increased over time and in 1669 he denounced the other members of the common council, including his namesake, John Knight who was mayor of Bristol in the following year, as fanatics. In 1681 he was fined for an assault, and for calling several members of the common council "papists, popish dogs, jesuits, and popish devils".
