Maynard was the second eldest son of
William Maynard, 2nd Baron Maynard of Estaines and his first wife Dorothy Banastre, daughter of Sir Robert Banastre of
Passenham, Northamptonshire. He travelled abroad in France, Italy, Germany and the Netherlands from 1660 to 1662. In 1663 he was elected
Member of Parliament for
Essex in a by-election to the
Cavalier Parliament. He was commissioner for assessment for Essex from 1663 to 1680 and commissioner for recusants in 1675. He was a
J.P. from April 1688 to his death and was commissioner for assessment for Essex again from 1689 to 1690. He succeeded to the peerage as Baron Maynard on the death of his father on 3 February 1699. ==Family==