In April 1660, Knatchbull was elected Member of Parliament for New Romney together with his father until the following year. In 1685 he succeeded his father as baronet and was elected MP for Kent.
In April 1660, Knatchbull was chosen as a Member of Parliament (MP) for New Romney alongside his father until the subsequent year. In 1685 he succeeded his father to become a baronet and was re-elected as an MP for Kent.