 On 1 May 1658 he was appointed Protector's serjeant, in which capacity he followed the Protector's bier on the ensuing 23 November.On the accession of Richard Cromwell he was made solicitor-general, and in parliament, where he sat for Newtown, Isle of Wight, lent the whole weight of his authority as a constitutional lawyer to prop up the Protector's tottering government.Maynard was involved in the founding of a school for girl's in Exeter when in 1658 he helped to found The Maynard School and Hele's School in the same year and he was also involved with the Grammar school at Totnes which like Maynard was endowed with funds under the will of Elizeeus Hele Esq who left considerable property for charitable purposes (Maynard was one of the trustees of his will).