Of a modest gentry family, Newbery trained as a lawyer, becoming a barrister in 1603. Not long thereafter he married into the Weldon family of Berkshire, two of whom had previously sat in Parliament for New Windsor, for which borough he became under-steward or recorder in 1608. On the death of his father in February 1611, Newbery inherited £100 in cash and some copyhold land held of the manor of Waltham, whose owner was Sir Henry Neville I* of Billingbear.
Returned for Windsor to the 1626 Parliament, during his second term as under-steward, Newbery proved surprisingly voluble for an inexperienced Member, making no less than 14 recorded speeches in addition to delivering one report from committee. He was also named to 30 committees, the first of which, on 14 Feb., concerned a bill to preserve the rights of ecclesiastical patrons, in which measure he had a personal interest as he controlled at least one advowson.
On 20 Feb. 1626 Newbery attacked the imposition on wine, urging ‘a Remonstrance to His Majesty, that the people that execute these unjust warrants may be sent for’. He was subsequently the third named member of the committee appointed to consider the matter. On the following day he returned to religion, reporting that there were 400 recusants in Berkshire alone. He was later appointed to help draft a new bill on recusants’ children (24 Mar.), and to consider bills ‘to direct the true and real conformity of popish recusants’ (8 May) and to provide better stipends for curates (9 May).
Despite having been appointed to consider a bill against adultery (4 Mar.), Newbery spoke on 21 Mar. for Sir Robert Howard* against the High Commission, which, being ‘but a new court’, ought ‘not to control this ancient court’ but rather ‘to be subject to this’. He was interrupted at this point, for not speaking to the question, but later in the debate he proposed that those members of the High Commission who were MPs should ‘be excluded and sent to the Tower’. A day later he was one of those ‘lawyers and others’, ordered to prepare a bill for the better payment of the Navy’s sailors, a matter moved by (Sir) Robert Pye and of particular concern to Newbery’s fellow Member for Windsor, Sir William Russell, the treasurer of the Navy.
For much of the Parliament Newbery displayed an ambivalent attitude towards the king’s chief minister, the duke of Buckingham.
Newbery remained in the Commons until the dissolution. Indeed, the day before the Parliament was brought to an end, his name headed the committee for a bill ‘for the better continuance of peace and unity in the church and commonwealth’.
In the autumn of 1630 Newbery escaped being fined for having failed to take up the order of knighthood at the Coronation after pleading with the commissioners for knighthood fines to take pity on him. For the last seven years, he claimed, he had endured ‘an incurable rupture in his body, which breedeth great infirmities’. Moreover, his means were severely limited: his annual income was only £20, he had recently had to pay the costs associated with ten lawsuits and he also had ‘a great charge of seven children, four of them being marriageable’.
